Miracle-dz/UniFAR-FTUs huggingface dataset:
Control and characterisation of a Rydberg spin system to explore many-body physics

This thesis explores the implementation of a spin-1/2 system to realise quantum simulation of Heisenberg XX and XXZ models. The spins are mapped onto two high-lying atomic levels, so-called Rydberg states, in an ultracold sample of 87Rb and coupled by a microwave field. Efficient synthesis and control of the driving field has been introduced in the setup in order to probe the spin dynamics with NMR sequences. Two- and three-photon excitation schemes are implemented to prepare the Rydberg spins. In order to spatially resolve the Rydberg excitation dynamics, a new imaging technique is employed, which uses the depletion of absorption in presence of Rydberg atoms to detect their distribution in the atomic cloud, revealing the emergence of spatial order of the Rydberg excitations due to strong van der Waals interactions. To benchmark the validity of this platform, the coherence of the spin ensemble is measured by Ramsey techniques in the low-density regime, where the single-spin dynamics accurately describes the observations. Despite the black-body redistribution of Rydberg spins setting a limit for the T2* time of the spin system, the coherence is measured to persist over long timescales on the order of 130 μs. Thus, scaling up the density of spins, first signatures of dipolar many-body effects for |nS⟩ − |nP⟩ (XX) and |nS⟩ − |(n + 1)S⟩ (XXZ) spin combinations have been observed.
Lattice Network Coding in Distributed Massive MIMO Systems

In this thesis, the uplink of distributed massive MIMO where a large number of distributed access point antennas simultaneously serve a relatively smaller number of users is considered. Lattice network coding (LNC), which comprises compute and forward (C&F) and integer forcing (IF), is employed to avoid the potentially enormous backhaul load. Firstly, novel algorithms for coefficient selection in C&F are proposed. For the first time, we propose a low polynomial complexity algorithm to find the optimal solution for the complex valued case. Then we propose a sub-optimal simple linear search algorithm which is conceptually sub-optimal, however numerical results show that the performance degradation is negligible compared to the exhaustive method. The complexity of both algorithms are investigated both theoretically and numerically. The results show that our proposed algorithms achieve better performance-complexity trade-offs compared to the existing algorithms. Both algorithms are suitable for lattices over a wide range of algebraic integer domains. Secondly, the performance of LNC in a realistic distributed massive MIMO model (including fading, pathloss and correlated shadowing) is investigated in this thesis. By utilising the characteristic of pathloss, a low complexity coefficient selection algorithm for LNC is proposed. A greedy algorithm for selecting the global coefficient matrix is proposed. Comprehensive comparisons between LNC and some other promising linear strategies for massive MIMO, such as small cells (SC), maximum ratio combining (MRC), and minimum mean square error (MMSE) are also provided. Numerical results reveal that LNC not only reduces the backhaul load, but also provides uniformly good service to all users in a wide range of applications. Thirdly, the inevitable loss of information due to the quantisation and modulo operation under different backhaul constraints are investigated. An extended C\&F with flexible cardinalities is proposed to adapt to the different backhaul constraints. Numerical results show that by slightly increasing the cardinality, the gap between C\&F to the infinite backhaul case can be significantly reduced.
Online Communities: A Case Study of the Office of the Future

This volume discusses "online" communities, where work is mediated and supported by a computer network. How do people react to spending much of their life online? What impacts does it have on the organization for productivity? The text addresses these issues by analyzing prototype systems of the mid 1980s that are desinged to provide answers to these questions in the future. The book should be of interest to those involved in the application and social impacts of computer-mediated communications systems and their design and evaluation inlcuding managers who must decide to implement such systems. It is also relevant for those interested in the relationship between technological innovation and soical change.
Exploring the Concept of Female Identity in Reproductive Health: A Systematic Review

Background: Women comprise one of the major population groups of any society that have been studied separately in recent decades due to their specific sexual, social, economic, and cultural traits. They make up half of the country’s population, so their potential abilities and injuries should not be neglected. Identity is a complex concept in social sciences that it is very difficult to reach a consensus on its definition. The aim of this study was to explore female identity through the systematic review of the literature. Methods: This was a systematic review in which the sources addressing female identity and its characteristics available in credible Persian and English databases were analysed. Then an operational definition was provided for the concept under study. To analyse the data, the text of each source was read carefully, and each sentence, phrase, or words contributing to the meaning, definition, attributes, and measurement of the concept were collected in a separate Microsoft Word file. In the next step, the data collected were coded and finally categorized. Results: The features of the concept of female identity in reproductive health appeared in three themes: Adaptation to the changes of the identity concept based on individual, temporal, and spatial conditions, facing life crises, and peace arising from constructive interactions. Conclusions: Female identity in reproductive health" is a dynamic, complex, and multidimensional concept comprising a set of characteristics, including adaptation with the changes of the concept of identity based on individual, temporal, and spatial circumstances, encountering life crises, and peace arising from constructive interactions.
MobiCom 2010 Poster : Frequency Quorum Rendezvous for Fast and Resilient Key Establishment under Jamming Attack

Jamming attacks have been studied as wireless security threats disrupting reliable RF communication in a wireless network. Existing countermeasures often make use of spread-spectrum techniques such as Frequency Hopping Spread Spectrum and Direct Sequence Spread Spectrum [3]. Communication parties rely on a pre-shared common key (hopping sequence or spread code) which is unknown to the jammer, thus making the system robust against jamming attacks. This, however, raises another issue: namely establishing the initial secure key pairing under jamming attacks. This demands another secure communication channel and this introduces circular dependency. To break the dependency between anti-jamming communications and key establishment, recent proposals [4, 5] adopted a Pseudo-random Frequency Hopping (PFH) technique similar to that in Bluetooth. During the key establishment, a sender and a receiver randomly switch over multiple frequencies. Upon meeting on the same frequency by chance, they exchange a common key. To increase the probability of encounters, the sender hops faster than the receiver. In Bluetooth, a master randomly hops every 625μs, whereas a slave switches frequencies every 11.25ms; thus the hopping ratio becomes 18 (= 625μs ). PFH, however, introduces considerable latency: it could take up to 100 seconds in the worst case [5]. Moreover, relying on random encounters among nodes cannot provide an upper bound of the time and cost to complete the key establishment phase. To resolve the problem, we propose a Frequency Quorum Rendezvous (FQR) scheme for fast and resilient key establishment. FQR exploits a quorum system which allows each node to build a hopping sequence independently during the key establishment phase. The intersection property of the quorum system increases probability that a pair of nodes meet within a bounded amount of time, during which they share a common key for future spread spectrum communications. We validate the proposed scheme via extensive simulations and present its robustness and efficiency.
Leads to Reduced Concreteness of Problem Elaborations: Evidence for the Avoidance Theory of Worry. Anxiety, Stress

Both lay concept and scientific theory have embraced the view that nonpathological worry may be helpful for defining and analyzing problems. To evaluate the quality of problem elaborations, concreteness is a key variable. Two studies with nonclinical student samples are presented in which participants elaborated topics associated with different degrees of worry. In Study 1, participants' elaborations were assessed using problem elaboration charts; in Study 2, they were assessed using catastrophizing interviews. When participants' problem elaborations were rated for concreteness, both studies showed an inverse relationship between degree of worry and concreteness: The more participants worried about a given topic the less concrete was the content of their elaboration. The results challenge the view that worry may promote better problem analyses. Instead they conform to the view that worry is a cognitive avoidance response.
Comparative assessment of semi-fragile watermarking techniques

Semi-fragile watermarking techniques aim to prevent tampering and fraudulent use of modified images. A semi-fragile watermark monitors the integrity of the content of the image but not its exact representation. Thus the watermark is designed so that if the content of the image has not been tampered with, and so long as the correct key is known and the image ha sufficiently high quality, the integrity is proven. However if some parts of the image is replaced by someone who does not possess the key, the watermark information will not be reliably detected, which can be taken as evidence of forgery. In this paper we compare the performance of nine semi-fragile watermarking algorithms in terms of their miss probability under forgery attack, and in terms of false alarm probability under mild, hence non-malicious signal processing operations that preserve the content and quality of the image. We propose desiderata for semi-fragile watermarking algorithms and indicate the promising algorithms among existing ones.
A Multi-Objective Genetic Algorithm for Solving Conflicted Goals in Questions Generating Problem

— Multi-objective genetic algorithm (MOGA) has been used for more than a decade to solve real-world optimization problems that have several, and often conflicting objectives. In this research, the conflicting objectives of achieving the maximum accuracy of the solution and at the same time minimizing the redundancy of the optimal solutions in retrieving the best set of exam questions for academicians for a particular subject are highlighted. Hence, the aim of this paper is to solve the multi-objective problem in a chromosome (solution) and also to maintain the fitness of the chromosome. The results of this research are measured based on the similarity achieved between the obtained and desired solutions. By using MOGA, a promising result is obtained with the maximum accuracy and simultaneously, minimizing the redundancy of the genes in a solution.
A joint-reconstruction approach for single-shot edge illumination x-ray phase-contrast tomography

Edge illumination X-ray phase-contrast tomography (EIXPCT) is an imaging technique that estimates the spatially variant X-ray refractive index and absorption distribution within an object while seeking to circumvent the limitations of previous benchtop implementations of X-ray phase-contrast tomography. As with gratingor analyzer-based methods, conventional image reconstruction methods for EIXPCT require that two or more images be acquired at each tomographic view angle. This requirement leads to increased data acquisition times, hindering in vivo applications. To circumvent these limitations, a joint reconstruction (JR) approach is proposed that concurrently produces estimates of the refractive index and absorption distributions from a tomographic data set containing only a single image per tomographic view angle. The JR reconstruction method solves a nonlinear optimization problem by use of a novel iterative gradient-based algorithm. The JR method is demonstrated in both computer-simulated and experimental EIXPCT studies.
Analysis of x-ray tomography data of an extruded low density styrenic foam: an image analysis study

Extruded styrenic foams are low density foams that are widely used for thermal insulation. It is difficult to precisely characterize the structure of the cells in low density foams by traditional cross-section viewing due to the frailty of the walls of the cells. X-ray computed tomography (CT) is a non-destructive, three dimensional structure characterization technique that has great potential for structure characterization of styrenic foams. Unfortunately the intrinsic artifacts of the data and the artifacts generated during image reconstruction are often comparable in size and shape to the thin walls of the foam, making robust and reliable analysis of cell sizes challenging. We explored three different image processing methods to clean up artifacts in the reconstructed images, thus allowing quantitative three dimensional determination of cell size in a low density styrenic foam. Three image processing approaches - an intensity based approach, an intensity variance based approach, and a machine learning based approach - are explored in this study, and the machine learning image feature classification method was shown to be the best. Individual cells are segmented within the images after the images were cleaned up using the three different methods and the cell sizes are measured and compared in the study. Although the collected data with the image analysis methods together did not yield enough measurements for a good statistic of the measurement of cell sizes, the problem can be resolved by measuring multiple samples or increasing imaging field of view.
Resonant dynamics of gravitationally bound pair of binaries: the case of 1:1 resonance

The work presents a study of the 1:1 resonance case in a hierarchical quadruple stellar system of the 2+2 type. The resonance appears if orbital periods of both binaries are approximately equal. It is assumed that both periods are significantly shorter than the period of principal orbit of one binary with respect to the other. In these circumstances, the problem can be treated as three independent Kepler problems perturbed by mutual gravitational interactions. By means of canonical perturbation methods, the planar problem is reduced to a secular system with 1 degree of freedom involving a resonance angle (the difference of mean longitudes of the binaries) and its conjugate momentum (involving the ratio of orbital period in one binary to the period of principal orbit). The resonant model is supplemented with short periodic perturbations expressions, and verified by the comparison with numerical integration of the original equations of motion. Estimates of the binaries periods variations indicate that the effect is rather weak, but possibly detectible if it occurs in a moderately compact system. However, the analysis of resonance capture scenarios implies that the 1:1 resonance should be exceptional amongst the 2+2 quadruples.
Information-Theoretic Properties of Exponential Families

This chapter contains sections titled: 19.1 Introduction, 19.2 Robustness of Exponential Family Codes, 19.3 Behavior at the ML Estimate β, 19.4 Behavior of the ML Estimate β, 19.5 Maximum Entropy and Minimax Codelength, 19.6 Likelihood Ratio Exponential Families and Renyi Divergences, 19.7 Summary
A Deuteron Quasielastic Event Simulation for CLAS12

One of the fundamental goals of nuclear physics is to understand the structure and behavior of strongly interacting nuclei in terms of its basic constituents, quarks and gluons. An important step towards this goal is the characterization of the internal structure of the nucleon; the elastic electric and magnetic form factors of the proton and neutron are key ingredients of this characterization. The elastic electromagnetic form factors are directly related to the charge and current distributions inside the nucleon and are among the most basic observables of the nucleon.
An immunity-based optimization algorithm for tuning neuro-fuzzy controller

Immune evolutionary algorithm is proposed based on the evolutionary principle in the immune system. In the algorithm, two new parameters of expansion radius and mutation radius are defined to construct a small neighborhood and a large neighborhood. Then expansion and mutation operations are designed to perform local and global search respectively by using the two neighborhoods, thus, two-level neighborhood search mechanism is realized. The results of multi-modal function optimization show that the algorithm has nice global and local searching performances. The algorithm is employed to design a neuro-fuzzy controller for real-time control of an inverted pendulum. In order to avoid the combinatorial explosion of fuzzy rules due to multivariable inputs, state variable synthesis scheme is suggested to reduce the number of fuzzy rules. Experimental results show that the designed controller can control actual inverted pendulum successfully.
Multiband nonthermal radiative properties of pulsar wind nebulae

Aims. The nonthermal radiative properties of 18 pulsar wind nebulae (PWNe) are studied in the 1D leptonic model. Methods. The dynamical and radiative evolution of a PWN in a nonradiative supernova remnant are self-consistently investigated in this model. The leptons (electrons/positrons) are injected with a broken power-law form, and nonthermal emission from a PWN is mainly produced by time-dependent relativistic leptons through synchrotron radiation and inverse Compton process. Results. Observed spectral energy distributions (SEDs) of all 18 PWNe are reproduced well, where the indexes of low-energy electron components lie in the range of 1.0–1.8 and those of high-energy electron components in the range of 2.1–3.1. Our results show that FX/Fγ > 10 for young PWNe; 1 < FX/Fγ ≤ 10 for evolved PWNe, except for G292.0+1.8; and FX/Fγ ≤ 1 for mature/old PWNe, except for CTA 1. Moreover, most PWNe are particle-dominated. Statistical analysis for the sample of 14 PWNe further indicate that (1) not all pulsar parameters have correlations with electron injection parameters, but electron maximum energy and PWN magnetic field correlate with the magnetic field at the light cylinder, the potential difference at the polar cap, and the spindown power; (2) the spin-down power positively correlates with radio, X-ray, bolometric, and synchrotron luminosities, but does not correlate with gamma-ray luminosity; (3) the spin-down power positively correlates with radio, X-ray, and γ-band surface brightness; and (4) the PWN radius and the PWN age negatively correlate with X-ray luminosity, the ratio of X-ray to gamma-ray luminosities, and the synchrotron luminosity.
First Principles Calculation of the Topological Phases of the Photonic Haldane Model

Photonic topological materials with a broken time-reversal symmetry are characterized by nontrivial topological phases, such that they do not support propagation in the bulk region but forcibly support a nontrivial net number of unidirectional edge-states when enclosed by an opaque-type boundary, e.g., an electric wall. The Haldane model played a central role in the development of topological methods in condensed-matter systems, as it unveiled that a broken time-reversal symmetry is the essential ingredient to have a quantized electronic Hall phase. Recently, it was proved that the magnetic field of the Haldane model can be imitated in photonics with a spatially varying pseudo-Tellegen coupling. Here, we use Green’s function method to determine from “first principles” the band diagram and the topological invariants of the photonic Haldane model, implemented as a Tellegen photonic crystal. Furthermore, the topological phase diagram of the system is found, and it is shown with first principles calculations that the granular structure of the photonic crystal can create nontrivial phase transitions controlled by the amplitude of the pseudo-Tellegen parameter.
Labor productivity assessment of three different mechanized harvest systems in Colombian oil palm crops

Labor shortages are increasingly problematic in rural areas worldwide and, in particular, in the oil palm sector in Colombia. Therefore, alternative methods and systems that increase labor productivity, such as using machines for collecting and lifting fresh fruit bunches (FFB), are needed. In oil palm cultivation, the most labor-intensive process is harvesting. We aimed to assess the labor productivity (in t · FFB/person/day) of three harvesting systems using mechanized lifting systems (harvest A: manual cutting, manual harvesting using meshes, carts, and livestock and lifting using a hydraulic arm; harvest B: manual cutting, manual harvest using a tractor, and lifting using a side-turning container; and harvest C: manual cutting, mechanized harvest using a tractor-grabber, and lifting using a side-turning container). Two bunch density scenarios were considered. Data were collected from adult palm crops in three oil palm plantations in the Eastern Plains of Colombia, and similar crop yields were obtained. Labor productivity was 1.20–2.53 t · FFB/person/day depending on the FFB density and the harvest system. Finally, the cost per ton harvested was $ 8.9–$ 16.6 per ton, being lower in the systems that demanded fewer personnel. The highest labor productivity and the lowest cost per ton harvested were obtained for harvest C.
ON MAPS AND GENERALIZED ?_s-SETS

In this paper we define the concepts of g. _s-continuous maps, g. _s-irresolute maps and g. V_s-closed maps by using generalized ? _s-sets and generalized V_s-sets. Also we introduce a new class of topological spaces called T^{V_s}-spaces.
UGGS: A Unified Graph Generation Framework Based on Self-Supervised Learning

Deep learning on graphs has gained interest in recent years. The applicability of graphs to model problems in various domains, such as chemical molecules, financial transactions, parse trees, etc., has encouraged researchers to develop and extend machine learning methods from other data modalities, such as text and image, to graphs. Generative models have been used extensively in recent years and have achieved significant milestones, especially in text and image generation. However, graph generative models have not been developed as extensively, and fundamental problems are still in the discussion phase. This work addresses some of these problems, such as the lack of an integrated framework and inter-pretable evaluation metric, by introducing a unified framework for the graph generation task. The base of the proposed framework is on the appropriate graph and node embeddings to estimate graphs’ distribution. Hence it composes of graph neural networks to embed the nodes and graphs and also enhances the quality of graph embeddings via the introduction of pseudo tasks in a self-supervised fashion. Self-supervised techniques have proven useful in enhancing generative models to be more robust and generalizable. This work proposes several pseudo tasks and evaluates their performance on common graph datasets. It also emphasizes the problem of graph decoding and speculates that graph generation strategy matters, and one can establish more complex graph generation models to generate higher-quality graphs. It also proposes a distance metric in embedding space for generated graphs to filter out poorly generated data. In the end, the proposed framework achieves competitive results compared to previously proposed models while having fewer parameters and a shorter training time. We have also made our framework implementation available.