Miracle-dz/UniFAR-FTUs huggingface dataset:
Passive Bistatic Radar Based on VHF DVB-T Signal

This paper presents the preliminary results of experiments utilizing the DVB-T signal transmitted in the VHF band to detect airborne targets in a passive coherent location (PCL) system. Thanks to the use of a commercial wideband transmitter working with a relatively long wavelength it is possible to obtain properties that are not available for higher frequency bands, such as UHF and microwave. Possibilities, such as foliage penetration while maintaining high resolution allow extended operational capabilities to be obtained. A system demonstrator performing such a task is presented in this paper along with processed results gathered during the measurement campaign. Thanks to a low-frequency operation, the radar hidden in the forest was able to detect an aircraft. The possibility of detection with radar hidden under foliage was compared to this obtained in the open field, which confirms the advantages and usability of the VHF DVB-T system as an illuminating signal for the PCL systems.
Computational Studies of Amoeboid Cell Motility in Three-dimensional Matrices

Tumor cells, upon loss of integrins or proteolytic machinery, are able to navigate through complex matrices through adhesion-independent or amoeboid mechanism. While adhesion dependent migration has been studied in both 2D and 3D environments, quantitative models of amoeboid motion in native environments are lacking. We have developed twoand threedimensional models of an amoeboid cell crawling through extracellular matrix (ECM) gaps using the finite element method. The model provides a powerful tool for the analysis of interactions between a cell and extracellular matrix and fluids in vitro and in vivo. The cell is modeled as an incompressible Newtonian fluid with surface tension on its boundary, where the chemotactic gradient induces the cell migration through a micro-channel. The relationships among the speed of the cell, diameter of a hole with respect to a size of the cell, the strength of the gradient, surface tension, and viscosity of the fluid inside/outside of the cell are calculated. Our results highlight the dependence of overall speed on both internal and external mechanochemical gradients, predict the centroid speed in 3D micro-channels and provide a quantitative framework to develop a fundamental understanding of complex cell motion in 3D environments.
A Novel Motion Compensation Approach Based on Symmetric Triangle Wave Interferometry for UAV SAR Imagery

The combination of synthetic aperture radar (SAR) with unmanned aerial vehicles (UAVs) is attractive for acquiring high-resolution images without the restrictions of time and weather. However, because UAVs are lightweight and small in size, the UAV SAR system is very sensitive to turbulence, resulting in serious trajectory deviations and remaining residual motion errors (RMEs), such as residual range cell migration (RCM) and aperture phase errors (APEs). In this paper, a novel motion compensation (MoCo) strategy is developed based on the symmetric triangle linear frequency modulated continuous wave (STLFMCW) signal. The STLFMCW signal model is first presented, which reveals the relevance between the positive-negative frequency modulations and motion errors. The residual RCMs and relative phase errors are estimated directly through the phase differential interferometry of up-ramp and down-ramp chirp signals, instead of the traditional approach of relying on the range-shift gradient of adjacent range profiles. The proposed approach is independent of conventional prominent point processing (PPP) and calculates the range deviation to avoid the accumulation of errors, thereby achieving high precision and efficiency. Experiments based on simulated and measured data sets validate the proposed approach.
Process-Oriented Optimization for Beyond 5G Cognitive Satellite-UAV Networks (Invited Paper)

The coverage area of terrestrial 4G/5G networks is usually limited, far from satisfying the communication demand in the remote rural, the post disaster and maritime scenarios. Both satellite and unmanned aerial vehicle (UAV) can be adopted to solve this problem in the 6G era. Towards this end, we consider a cognitive satellite-UAV network (CSUN), where satellite and UAVs are managed in a coordinated manner, and opportunistically share spectrum to alleviate the spectrum scarcity problem. Particularly, we use the UAV swarm to mitigate the satellite-UAV interference. Motivated by practical applications, the limited on-board energy and imperfectly acquired channel state information (CSI) are discussed. We propose a process-oriented optimization scheme to maximize the data transmission efficiency, which jointly optimizes the transmit power and hovering time of UAV swarm for the whole flight process. The scheme takes both energy constraints and interference power constraints into account, and performs in an iterative way. Simulation results demonstrate the superiority of the proposed algorithm, which could be an effective solution for extending the coverage performance of terrestrial 4G/5G networks.
Deep Periocular Recognition: A Case Study

The periocular region of a face can be used as an autonomous modality in a biometric recognition system. We evaluate two different deep learning pipelines, one with a specific segmentation step and one without it, and show the positive and negative properties of both of them. The obtained results on the newly introduced public dataset SBVPI show that the periocular region offers enough distinguishing information for successful identity recognition.
Analysis and Simulation of Single Tail and Double Tail Circuits

This High performance comparator circuits are imperative and indispensable modules for the implementation of integrated circuit data converter architectures to be utilized for different wireless portable electronic systems. The comparator works shown in this paper explores two different architectures by giving strong importance to specifications such as offset voltage (mV), power dissipation (µW), voltage gain (dB), kick back noise reduction, propagation delay (ps) and speed-power product (fJ). The modified double tail comparator uses regenerative feedback to convert the output to a full scale digital output signal. The circuit can accept both negative and positive voltages. This works presents the comprehensive analysis and simulation of two comparator circuits and is carried out in CMOS 0. 13µm technology. An integrated circuit designer can completely balance the tradeoffs such as reduction of power consumption, circuit speed, and offset voltage minimization for the comparator circuit.
Experimental Results of Polarimetric Passive ISAR Exploiting DVB-S2 Illumination

This paper shows a first analysis of polarimetric passive ISAR images using digital video broadcasting-satellite (DVB-S(2)) as illuminator of opportunity. A measurement campaign has been conducted exploiting an experimental system developed at Fraunhofer FHR and a ferry as cooperative target. The collected data have been firstly processed by means of backprojection to obtain ISAR images at each polarimetric channel. Then two different representations in the polarimetric domain are considered. The first one is a color coding based on a modified Pauli decomposition. The second one is the evaluation of the determinant of the Sinclair scattering matrix. From both representations we can recognize that different scattering mechanisms within the same target behave differently in the polarimetric domain. The analysis is conducted on two different data sets with distinct bistatic geometries. The retrieved results assess the usefulness of the polarimetric information in passive ISAR images.
Robust Active Visual SLAM System Based on Bionic Eyes

Visual simultaneously localization and mapping (SLAM) systems obtain accurate estimation of the camera motion and the 3D map of the environment. Although the performance of SLAM systems is very impressive in many common scenarios, the tracking failure is still a very challenging issue, which always exists in the low textured environment and the rapid camera motion situation. In this paper, we proposed the first active bionic eyes SLAM system that leverages saccade movement of human eyes. In order to find more features points, we proposed an autonomous control strategy of the bionic eyes, which is mainly inspired by the peripheral and central visual of human eyes. Experimental results support that compared to fixed stereo cameras, our active bionic eyes SLAM system gains more robustness and avoids the tracking failure problem when facing the low textured environment.
Non-Asymptotic Linear Growth of Energy Efficiency in Distributed Autonomous D2D MIMO Wireless Communications

Device-to-device (D2D) communications is a cell-free enabler of 5G and rising wireless communications demand between low-orbit satellite constellation, self-driving vehicles and unmanned aerial systems. Distributed computation (where channel state information is not available) schemes facilitate direct exchanges between mobile user equipment (UE) and if necessary a UE can serve as a relay. Thus, it is essential to develop robust D2D communications frameworks agnostic to the channel distribution which can deliver scalable data rates to self-driving vehicles while the spectral efficiency(SE) is non-asymptotic and energy consumption is increasing to yield an energy efficiency (EE) that is a unimodal function. In this paper, we evaluate the optimal EE by using the computation of the SE in distributed multiple input- multiple output (MIMO) wireless communications. A generalized water-filling framework over arbitrary channel distribution is used to evaluate the SE and then the EE to compare with single-input single-output optimized approximate schemes based on Taylor expansion. The computation yields the optimal power allocation at the transmitters which is derived to illustrate the performance gain of the generalized water-filling distributed MIMO over the approximate scheme. Our simulations results show novel achievable EE linear growth as a function of SE and robust trade-offs in performance gains determined by the total power consumption optimal profile when switching MIMO dimensions. Our trade-off prevents power consumption while EE is decreasing. Thus by switching the number of MIMO operating antenna elements at both the receiver and transmitter sides, EE is no more a unimodal function as illustrated in the literature.
V2iFi

Given the significant amount of time people spend in vehicles, health issues under driving condition have become a major concern. Such issues may vary from fatigue, asthma, stroke, to even heart attack, yet they can be adequately indicated by vital signs and abnormal activities. Therefore, in-vehicle vital sign monitoring can help us predict and hence prevent these issues. Whereas existing sensor-based (including camera) methods could be used to detect these indicators, privacy concern and system complexity both call for a convenient yet effective and robust alternative. This paper aims to develop V2iFi, an intelligent system performing monitoring tasks using a COTS impulse radio mounted on the windshield. V2iFi is capable of reliably detecting driver's vital signs under driving condition and with the presence of passengers, thus allowing for potentially inferring corresponding health issues. Compared with prior work based on Wi-Fi CSI, V2iFi is able to distinguish reflected signals from multiple users, and hence provide finer-grained measurements under more realistic settings. We evaluate V2iFi both in lab environments and during real-life road tests; the results demonstrate that respiratory rate, heart rate, and heart rate variability can all be estimated accurately. Based on these estimation results, we further discuss how machine learning models can be applied on top of V2iFi so as to improve both physiological and psychological wellbeing in driving environments.
A Novel Review Helpfulness Measure Based on the User-Review-Item Paradigm

Review platforms are viral online services where users share and read opinions about products (e.g., a smartphone) or experiences (e.g., a meal at a restaurant). Other users may be influenced by such opinions when deciding what to buy. The usability of review platforms is currently limited by the massive number of opinions on many products. Therefore, showing only the most helpful reviews for each product is in the best interest of both users and the platform (e.g., Amazon). The current state of the art is far from accurate in predicting how helpful a review is. First, most existing works lack compelling comparisons as many studies are conducted on datasets that are not publicly available. As a consequence, new studies are not always built on top of prior baselines. Second, most existing research focuses only on features derived from the review text, ignoring other fundamental aspects of the review platforms (e.g., the other reviews of a product, the order in which they were submitted). In this article, we first carefully review the most relevant works in the area published during the last 20 years. We then propose the User-Review-Item (URI) paradigm, a novel abstraction for modeling the problem that moves the focus of the feature engineering from the review to the platform level. We empirically validate the URI paradigm on a dataset of products from six Amazon categories with 270 trained models: on average, classifiers gain +4% in F1-score when considering the whole review platform context. In our experiments, we further emphasize some problems with the helpfulness prediction task: (1) the users’ writing style changes over time (i.e., concept drift), (2) past models do not generalize well across different review categories, and (3) past methods to generate the ground truth produced unreliable helpfulness scores, affecting the model evaluation phase.
What makes a trophy hunter? An empirical analysis of Reddit discussions

In this paper, an empirical data-driven analysis of online discussions of meta-game reward systems is carried out. The data is collected from one of the biggest online discussion forums called Reddit and a text-mining technique called topic modeling is employed. Over 46000 discussion threads from the two most relevant subreddits /r/xboxachievements and /r/Trophies are analyzed and the results of topic modeling shows not only interesting topics but also the (dis)similarity between two text sources the temporal trends of topics. We have found that the volume of related discussions shows an ongoing trend. The topic model results have also revealed that some game genres are more prevalent than others and the (dis)similarities between text sources have been also discovered.
Abstract. The study aimed to investigate the role of low-dose dobutamine stress myocardial contrast echocardiography (MCE) in evaluating myocardial local microcirculation and predicting cardiac function recovery in patients with myocar-

The study aimed to investigate the role of low-dose dobutamine stress myocardial contrast echocardiography (MCE) in evaluating myocardial local microcirculation and predicting cardiac function recovery in patients with myocardial infarction. A total of 50 patients with acute myocardial infarction (AMI) were enrolled in the present study. Positron emission tomography was used as a gold standard to determine viable/non-viable myocardial segments in infarcted myocardial region. MCE and dobutamine stress MCE were carried out 72 h after PCI. MCE was carried out again to evaluate myocardial condition at 6 months after PCI. As compared with normal myocardial segments, resting MCE revealed a significant decrease of the values of A (the peak intensity of the time‐perfusion intensity curve, reflecting the myocardial blood volume), β (the slope of the curve, reflecting the myocardial blood flow (MBF) velocity) and A x β (reflecting MBF) of viable and non‐viable myocardial segments. After being challenged by dobutamine, the values of A, β and A x β of normal coronary blood supply areas were significantly increased; while the segments A and A x β of viable myocardium were markedly decreased. Patients were further divided into two groups based on the changes in the contrast-enhanced index (CSI) following dobutamine loading. In the dobutamine stress echocardiography‐positive group (the CSI increased or decreased by >0.2), the left ventricular ejection fraction was significantly increased and pro-B‐type natriuretic peptide significantly decreased at 6 months following intervention. Low-dose dobutamine stress MCE was indicated to be an effective method to evaluate myocardial microcirculation perfusion in patients with AMI following PCI. In addition, CSI, as a simple semi‐quantitative index, may predict left ventricular function in patients with AMI.
CIMA: A Large Open Access Dialogue Dataset for Tutoring

One-to-one tutoring is often an effective means to help students learn, and recent experiments with neural conversation systems are promising. However, large open datasets of tutoring conversations are lacking. To remedy this, we propose a novel asynchronous method for collecting tutoring dialogue via crowdworkers that is both amenable to the needs of deep learning algorithms and reflective of pedagogical concerns. In this approach, extended conversations are obtained between crowdworkers role-playing as both students and tutors. The CIMA collection, which we make publicly available, is novel in that students are exposed to overlapping grounded concepts between exercises and multiple relevant tutoring responses are collected for the same input. CIMA contains several compelling properties from an educational perspective: student role-players complete exercises in fewer turns during the course of the conversation and tutor players adopt strategies that conform with some educational conversational norms, such as providing hints versus asking questions in appropriate contexts. The dataset enables a model to be trained to generate the next tutoring utterance in a conversation, conditioned on a provided action strategy.
A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.
Negotiating belonging and perceptions of citizenship in a transnational world: Singapore, a cosmopolis?

The complex mappings of inflows and outflows of people, capital, images and ideas in global city spaces create particular challenges for nation-states that are deeply embedded in the international circuit of capital. Through an empirical study of Singapore, an aspiring global city-state, I offer an analysis of how the state-sponsored cosmopolitan project is contested by Singapore citizens. I also present evidence to highlight the contradictions of belonging and citizenship in a transnational world, with particular reference to the postcolonial racial and nationality dynamics that inflect these discourses. Négocier l'appartenance et les perceptions de la citoyenneté dans un monde transnational: Singapour comme ville cosmopolite? Les mappages complexes des mouvements des personnes, du capital, des images et des idées à travers les espaces urbains mondiaux posent un défi particulier aux états-nations qui sont très fortement intégrés dans le circuit international du capital. Singapour, ville-état mondiale en croissance, est le sujet d'une étude empirique dans laquelle je présente une analyse du projet cosmopolite soutenu par l'état et comment ce projet est contesté par les citoyens de Singapour. Je présente également des éléments de preuve pour faire ressortir les contradictions entre l'appartenance et la citoyenneté dans un monde transnational, en précisant entre autres les dynamiques qui touchent aux identités raciales et nationales postcoloniales qui pèsent sur ces discours. Mots-clefs: appartenance, citoyenneté, mobilité transnationale, cosmopolitanisme, Singapour. La negociación de pertenencia e ideas de ciudadanía en un mundo transnacional: Singapur, ¿un cosmópolis? Los complejos mapeos de la entrada y salida de personas, capital, imágenes e ideas en los espacios de ciudades globales crean desafíos particulares para naciones-Estados, los cuales están estrechamente vinculados al circuito internacional de capital. Por un estudio empírico de Singapur, que aspira a ser reconocido como ciudad-estado global, ofrezco un análisis de cómo los ciudadanos de Singapur contestan este proyecto cosmopólito patrocinado por el Estado. También presento pruebas para destacar las contradicciones inherentes en las nociones de pertenencia y ciudadanía en un mundo transnacional, con referencia particular a la dinámica racial y de la dinámica de nacionalidad poscolonial que salpican estos discursos. Palabras claves: pertenencia, ciudadanía, movilidad transnacional, cosmopolitanismo, Singapur.
How Globalized Really is European Trade?

Abstract Using a new set of measures of concentration of trade, I suggest that the opening up of trade to date has been greatly exaggerated. At least judging on the basis of trade concentration, agriculture and service sectors should barely be seen as globalized at all. Contrary to other, recent studies, Europe's main economies lag behind the USA in terms of global openness, and most are behind Japan, Canada and China. The Balkans, Poland and the Czech Republic are near the bottom end of the global openness league table. Since there is a strong correlation between concentration of trade and poor economic performance, this should be of concern to those countries and to the EU.
Convexity and optimization with copulæ structured probabilistic constraints

Probability constraints play a key role in optimization problems involving uncertainties. These constraints request that an inequality system depending on a random vector has to be satisfied with a high enough probability. In specific settings, copulæ can be used to model the probabilistic constraints with uncertainty on the left-hand side. In this paper, we provide eventual convexity results for the feasible set of decisions under local generalized concavity properties of the constraint mappings and involved copulæ. The results cover all Archimedean copulæ. We consider probabilistic constraints wherein the decision and random vector are separated, i.e. left/right-hand side uncertainty. In order to solve the underlying optimization problem, we propose and analyse convergence of a regularized supporting hyperplane method: a stabilized variant of generalized Benders decomposition. The algorithm is tested on a large set of instances involving several copulæ among which the Gaussian copula. A Numerical comparison with a (pure) supporting hyperplane algorithm and a general purpose solver for non-linear optimization is also presented.