Miracle-dz/UniFAR-FTUs huggingface dataset:
Ring-Resonator Based Widely-Tunable Narrow-Linewidth Si/InP Integrated Lasers

This paper presents recent results on widely-tunable narrow-linewidth semiconductor lasers using a ring-resonator based mirror as the extended cavity. Two generations of lasers on the heterogeneous Si/InP photonic platform are presented. The first-generation lasers, with a total footprint smaller than 0.81 mm2, showed an intrinsic linewidth of ∼2 kHz over a 40 nm wavelength tuning range across C+L bands. The second-generation lasers using ultra-low loss silicon waveguides and a novel cavity design achieved an intrinsic linewidth below 220 Hz. The lasers also possess an ultrawide wavelength tuning range of 110 nm across three optical communication bands (S+C+L). These are records among all fully integrated semiconductor lasers reported in the literature.
Time-Frequency-Resolved Absolute Time Delay of the Photoelectric Effect

This thesis reports experiments and numerical calculations aiming at the observation and quantitative dissection of the microscopic mechanisms contributing to the temporal delays observed in time-resolved measurements of the attosecond photoelectric effect, i.e. the delayed appearance of the photoelectron in vacuum after excitation of metallic samples in with extreme-ultraviolet (XUV) radiation. We probe photoelectrons emerging from the metal surface and their respective frequency-resolved time delays with temporal resolution and accuracy on the 10 attoseconds time scale.
Testing Brain-Computer Interfaces with Airplane Pilots under New Motor Imagery Tasks

The purpose of a brain–computer interface (BCI) is the recording of brain signals to translate them into commands. This work proposes new naturalistic and intuitive motor imagery (MI) BCI task for aircraft Pilots for a BCI System, and explore if they take advantage of their previous motor experience in MI–BCI experiments. Results show that Pilots get better performance than a control group and that it is possible to get good classification accuracy results with new naturalistic MI tasks.
Adaptive spectrum-shared association for controlled underlay D2D communication in cellular networks

This study proposes adaptive downlink association schemes for controlled device-to-device (D2D) communication in cellular networks. The proposed schemes utilise active devices under specific conditions to improve the network performance. Specifically, active devices are classified into two disjoint groups according to their individual quality of service (QoS) requirements from their base station (BS). The BS adaptively allocates downlink physical channels to meet individual QoS of devices using a minimal number of these available channels. The unused channels at each served device (in the first class) can be then utilised by that device to serve other devices from the second class, which are not served by the BS, via controlled D2D associations. Herein, D2D pair discovery as well as the conditions for establishing successful D2D association between the classified devices are treated. Furthermore, two D2D association schemes that vary in terms of their performance and implementation complexity to meet certain objectives at the device of interest are presented. The developed analytical results address the scenarios of idealised perfect and practical imperfect D2D association. Numerical results are provided to further explain the performance variations between the proposed association schemes under perfect and imperfect operation scenarios.
Skew-normal Bayesian spatial heterogeneity panel data models

ABSTRACT This paper proposes a new regression model for the analysis of spatial panel data in the case of spatial heterogeneity and non-normality. In empirical economic research, the normality of error components is a routine assumption for the models with continuous responses. However, such an assumption may not be appropriate in many applications. This work relaxes the normality assumption by using a multivariate skew-normal distribution, which includes the normal distribution as a special case. The methodology is illustrated through a simulation study and application to insurance and gasoline demand data sets. In these analyses, a simple Bayesian framework that implements a Markov chain Monte Carlo algorithm is derived for parameter estimation and inference.
GLOBAL SINGULAR BOUNDARY METHOD FOR SOLVING 2D NAVIER–STOKES EQUATIONS

This article presents a numerical algorithm based on the singular boundary method (SBM) for the incompressible steady Navier–Stokes equations formulated using primitive variables. The SBM with the Stokeslet fundamental solution and dual reciprocity (DR) principle has been chosen to solve the nonlinear flow equations. The particular solution of the non-homogeneous Stokes equations is constructed as a linear combination of implicitly local radial basis function. The simple direct iterative scheme was used to handle nonlinearities of Navier–Stokes equations with a variation of the non-homogeneous term of the particular solution. The non-homogeneous term is formed using the nonlinear convective terms of the momentum equations, evaluated using values from previous iterations. It is found that SBM with a localized DR principle gives reasonable results for numerical problems of lid-driven cavity flow up to Re = 3200, and the backward-facing step at Re = 800.
Extreme UV secondary electron yield measurements of Ru, Sn, and Hf oxide thin films

Abstract. Background: The secondary electron yield (SEY) of materials is important for topics as nanoparticle photoresists and extreme ultraviolet (EUV) optics contamination. Aim: Experimentally measure SEY and secondary electron energy distributions for Ru, Sn, and Hf oxide. Approach: The SEY and energy distribution resulting from 65 to 112 eV EUV radiation are measured for thin-film oxides or films with native oxide. Results: The total SEY can be explained by EUV absorption in the topmost nanometer of (native) oxide of the investigated materials. Conclusions: Although the relative SEY of Ru and Sn is well-explained by the difference in EUV absorption properties, the SEY of HfO2 is almost a factor 2 higher than expected. Based on the energy distribution of secondary electrons, this may be related to a lower barrier for secondary electron emission.
Determining image sensor temperature using dark current

ABSTRACT The state of the art method for fingerprinting digital cameras focuses on the non-uniform output of an array of photodiodes due to the distinct construction of the PN junction when excited by photons. This photo-response non-uniformity (PRNU) noise has shown to be effective but ignores knowledge of image sensor output under equilibrium states without excitation (dark current). The dark current response (DSN) traditionally has been deemed unsuitable as a source of fingerprinting as it is unstable across multiple variables including exposure time and temperature. As such it is currently ignored even though studies have shown it to be a viable method similar to that of PRNU. We hypothesize that DSN is not only a viable method for forensic identification but, through proper analysis of the thermal component, can lead to insights regarding the specific temperature at which an individual image under test was taken. We also show that digital filtering based on the discrete cosine transformation, rather than the state-of-the-art wavelet filtering, there is significant computational gain albeit with some performance degradation. This approach is beneficial for triage purposes.
Theta correspondence for symplectic-orthogonal and metaplectic-orthogonal p-adic dual pairs

In this paper, we completely describe the Howe correspondence for the dual pairs from the title over a nonarchimedean local field of characteristic zero. More specifically, for every irreducible admissible representation of these groups, we find its first occurrence index in the theta correspondence and we describe, in terms of their Langlands parameters, the small theta lifts on all levels.
INTEGRATION OF HSP90 INHIBITION IN COMBINATIONAL IMMUNOTHERAPIES TARGETING RECEPTOR TYROSINE KINASE EPHA2

﻿Limitations in CD8+ T cell recognition of tumor cells due to defects in their antigen processing machinery or the selection of variants expressing low or absent levels of cognate tumor antigens have been previously identified as impediments to effective cancer immunotherapy. Hence, treatment regimens that coordinately promote enhanced activation of anti-tumor CD8+ T cells, improved delivery of such effector cells into tumor sites, and augmented recognition of tumor or tumor-associated stromal cells by therapeutic CD8+ T cells, would be expected to yield greater clinical benefit. Using an MCA205 sarcoma model, I show that in vitro treatment of tumor cells with the HSP90 inhibitor 17-DMAG results in the transient (proteasome-dependent) degradation of the HSP90 client protein EphA2 and the subsequent increased recognition of tumor cells by Type-1 anti-EphA2 CD8+ T cells. In vivo administration of 17-DMAG to tumor-bearing mice led to: i. ) slowed tumor growth; ii. ) enhanced/prolonged recognition of tumor cells by anti-EphA2 CD8+ T cells; iii. ) reduced levels of myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg) in the tumor microenvironment (TME); and iv. ) activation of tumor-associated vascular endothelial cells in association with elevated levels of Type-1 tumor infiltrating lymphocytes (TIL). When combined with EphA2-specific active vaccination or the adoptive transfer of EphA2-specific CD8+ T cells, 17-DMAG cotreatment yielded a superior tumor therapeutic regimen that was capable of rendering animals free of disease.
Performance Limits of Visible Light-Based User Position and Orientation Estimation Using Received Signal Strength Under NLOS Propagation

In this paper, we aim at providing a unified performance analysis framework for visible light-based positioning (VLP) using received signal strength (RSS), which can be used to gain insights into improving the performance of RSS-based VLP systems. Specifically, we first obtain a closed-form Cramer-Rao lower bound (CRLB) for the user equipment (UE) location and orientation, respectively. Then, we reveal the impact of the signal-to-noise ratio (SNR), transmission distance, prior knowledge and the number of LED sources on the RSS-based VLP performance. Moreover, the impact of the non-line-of-sight (NLOS) propagation on the RSS-based VLP performance is studied. It is shown that the RSS-based VLP performance will hit an error floor caused by the unknown NLOS links. These NLOS-caused UE location and orientation error floors in the high SNR region are analyzed. Finally, the information contribution of each LED source is studied to give an intuitive understanding on the impact of the LED array geometry on the RSS-based VLP performance. The obtained CRLB and the associated VLP performance analysis form a theoretical basis for the design of efficient VLP algorithms and VLP performance optimization strategies (e.g., resource allocation and smart LED source selection).
Cellular-Connected UAV: Uplink Association, Power Control and Interference Coordination

The line-of-sight (LoS) air-to-ground channel brings both opportunities and challenges in cellular-connected unmanned aerial vehicle (UAV) communications. On one hand, the LoS channels make more cellular base stations (BSs) visible to a UAV as compared to the ground users, which leads to a higher macro-diversity gain for UAV-BS communications. On the other hand, they also render the UAV to impose/suffer more severe uplink/downlink interference to/from the BSs, thus requiring more sophisticated inter-cell interference coordination (ICIC) techniques with more BSs involved. In this paper, we consider the uplink transmission from a UAV to cellular BSs, under spectrum sharing with the existing ground users. To investigate the optimal ICIC design and air-ground performance trade-off, we maximize the weighted sum-rate of the UAV and existing ground users by jointly optimizing the UAV’s uplink cell associations and power allocations over multiple resource blocks. However, this problem is non-convex and difficult to be solved optimally. We first propose a centralized ICIC design to obtain a locally optimal solution based on the successive convex approximation (SCA) method. As the centralized ICIC requires global information of the network and substantial information exchange among an excessively large number of BSs, we further propose a decentralized ICIC scheme of significantly lower complexity and signaling overhead for implementation, by dividing the cellular BSs into small-size clusters and exploiting the LoS macro-diversity for exchanging information between the UAV and cluster-head BSs only. Numerical results show that the proposed centralized and decentralized ICIC schemes both achieve a near-optimal performance, and draw important design insights based on practical system setups.
A Study on the Impact of Packet Length on Communication in Low Power Wireless Sensor Networks Under Interference

Reliability is nowadays considered a key requirement in wireless sensor networks for their increasing diffusion in various Internet of Things applications. However, radio interference from various sources may heavily affect the performance of wirelessly connected embedded devices, resulting into increased packet collisions and congestions. There is therefore a widely recognized need of both theoretical and practical investigations capable of shedding light on the factors affecting the operativeness of sensor networks subject to interference. In this paper, we investigate the role of packet length into the reliability and energy efficiency of low-power medium access protocols. Specifically, we propose a mathematical model to explore the functional dependence of the reliability of a pair of sensor nodes under interference from packet length. We also present a wide range of experimental evaluations aimed at validating the model and at providing novel insights on dependability issues. In particular, we assess the performance of Contiki’s default medium access control layer (together with that of an always listening receiver, as a baseline) in terms of packet loss rate and energy efficiency for varying payload lengths. Experimental results highlight the interplay between packet size and interference and in particular the tradeoff between the robustness against interference and the overhead imposed to communication as a function of the length of data packets. The Pareto curve describing the energy efficiency as a function of the packet loss rate, demonstrates the existence of intermediate packet size representing an optimal choice for balancing energy consumption and communication reliability, enabling adequate system dimensioning at design-level.
Asymptotic behavior of the solution of the space-dependent variable-order fractional diffusion equation : ultra-slow anomalous aggregation

We find the asymptotic representation of the solution of the variable-order fractional diffusion equation, which remains unsolved since it was proposed in [Checkin et. al., J. Phys. A, 2005]. We identify a new advection term that causes ultra-slow spatial aggregation of subdiffusive particles due to dominance over the standard advection and diffusion terms, in the long-time limit. This uncovers the anomalous mechanism by which non-uniform distributions can occur. We perform Monte Carlo simulations of the underlying anomalous random walk and find good agreement with the asymptotic solution.
Lock-in phenomenon of vortex shedding in oscillatory flows: an analytical investigation pertaining to combustors

An analytical investigation is performed to understand the lock-in phenomenon, observed in vortex shedding combustors. Several aeroengine afterburners and ramjets use a bluff body to stabilize the flame. The bluff body sheds vortices. During the occurrence of high-amplitude combustion instability, the frequency of vortex shedding locks in to the frequency of the chamber acoustic field. This phenomenon is termed vortex-acoustic lock-in. In general, there is a two-way coupling between the vortex shedding process and the acoustic field, making analytical investigation difficult. Since the frequency of the latter remains largely unaltered, performing an investigation to study the response of vortex shedding to external excitation not only allows one to gain insights, but also make the problem analytically tractable. We begin with a lower-order model available in the literature to describe the vortex shedding process in non-reacting flows, arising from sharp corners in the presence of upstream velocity excitation. The continuous time domain model is transformed to a discrete map, which connects the time instances of two successive vortex shedding events. The frequency and amplitude of excitation are varied to study the instantaneous vortex shedding time period, as the response of the system. In the absence of forcing, the iterates of the map form a period-1 solution with the frequency equalling the natural vortex shedding frequency. On increasing the amplitude of excitation, quasi-periodic behaviour of the iterates is observed, followed by a period-1 lock-in solution, where vortex shedding occurs at the excitation frequency. On further increasing the amplitude, de-lock-in occurs. From the map, an analytical solution is extracted, which represents the lock-in state. The condition and thereby the region in the frequency–amplitude parameter space where a general $p:1$ lock-in occurs is then identified. Several important analytical expressions, such as for (1) critical threshold frequency above which lock-in occurs, (2) boundary of lock-in region in the parameter space, that are of direct importance to the design of quieter combustors are obtained. The study also identifies the transition of higher-order $p:1$ to $1:1$ lock-in state, through a series of lock-in and de-lock-in steps, whose occurrence could be verified from future experiments.
Ultrahigh-Sensitivity Microwave Sensor for Microfluidic Complex Permittivity Measurement

The conventional resonant-type microwave microfluidic sensors made of planar resonators suffer from limited sensitivities. This is due to the existence of several distributed capacitors in their structure, where just one of them acts as a sensing element. This article proposes a very high-sensitivity microwave sensor made of a microstrip transmission line loaded with a shunt-connected series LC resonator. A large sensitivity for dielectric loadings is achieved by incorporating just one capacitor in the resonator structure. Applying sample liquids to the microfluidic channel implemented in the capacitive gap area of the sensor modifies the capacitor value. This is translated to a resonance frequency shift from which the liquid sample is characterized. The sensor performance and working principle are described through a circuit model analysis. Finally, a device prototype is fabricated, and experimental measurements using water/ethanol solutions are presented for verification of the sensing principle.
Dynamics of neon ions after neon gas seeding into tokamak plasma

Two dimensional interchange turbulence has been used to describe neon gas interaction with tokamak plasma, and is able to include anomalous transport effects self-consistently in the edge and scrape-off layer (SOL) regions. Model equations related to the plasma turbulence coupled with neon gas have been solved numerically using the BOUT++ framework code. Two different fluid models of the neon gas have been investigated, and in this context a few results related to the Aditya tokamak are presented. Numerical results indicate that ionization and radiative cooling processes modify the plasma turbulence. The existence of neon ions and their radial profile in the edge and SOL regions are the most significant results in this work. This new result has been investigated in detail in the presence of the interchange plasma turbulence. Other relevant results such as an increase of plasma density and a small change of electron temperature are also presented. In turbulence saturated states the electron temperature can increase slightly even in the presence of radiative cooling. Neon ions in the presence of polarization drift and radiative cooling modify the radial electric field and its radial shear. Radial electron energy flux has been investigated in the context of poloidal velocity shear and turbulence decorrelation rates. An increase of the electron energy confinement time has been observed numerically, mainly in the SOL region in the presence of gas seeding. Experimental results show an increase of global energy confinement time only when the gas seeding becomes effective in changing the global plasma parameters.
Energy-fair and flexible bandwidth-based routing in multi-domain green networks

Although green networking and fairness are both vital and rapidly increasing areas of research, providing energy-fairness in multi-domain green networks is a hitherto unexplored issue. In this study, the authors address energy-fair routing in multi-domain green networks by formulating an optimisation problem as an integer linear programme. The authors' problem maximises the energy saving of the domain with minimum energy saving while ensuring that the energy consumption of each domain is below a given threshold. The model they have established in this study also provides a flexible bandwidth assignment mechanism which improves the feasibility performance of their methods. They then propose a polynomial-time heuristic algorithm for this problem. They evaluate the performance of their heuristic algorithm by comparison with the results obtained from their integer linear programming formulation using optimisation software CPLEX. The simulation results demonstrate that the heuristic algorithm yields close results to the values obtained from the CPLEX implementation of their proposed formulation in terms of energy-fairness and outperforms the previous results while at the same time having low computational complexity.
Interstellar Plunging Waves: ALMA Resolves the Physical Structure of Nonstationary MHD Shocks

Magnetohydrodynamic (MHD) shocks are violent events that inject large amounts of energy in the interstellar medium dramatically modifying its physical properties and chemical composition. Indirect evidence for the presence of such shocks has been reported from the especial chemistry detected toward a variety of astrophysical shocked environments. However, the internal physical structure of these shocks remains unresolved since their expected spatial scales are too small to be measured with current instrumentation. Here we report the first detection of a fully spatially resolved, MHD shock toward the infrared dark cloud (IRDC) G034.77-00.55. The shock, probed by silicon monoxide (SiO) and observed with the Atacama Large Millimeter/submillimeter Array (ALMA), is associated with the collision between the dense molecular gas of the cloud and a molecular gas flow pushed toward the IRDC by the nearby supernova remnant (SNR) W44. The interaction is occurring on subparsec spatial scales thanks to the enhanced magnetic field of the SNR, making the dissipation region of the MHD shock large enough to be resolved with ALMA. Our observations suggest that molecular flow–flow collisions can be triggered by stellar feedback, inducing shocked molecular gas densities compatible with those required for massive star formation.