Miracle-dz/UniFAR-FTUs huggingface dataset:
A Satisficing Control Design Framework with Safety and Performance Guarantees for Constrained Systems under Disturbances

This paper presents a safe robust policy iteration (SR-PI) algorithm to design controllers with satisficing (good enough) performance and safety guarantee. This is in contrast to standard PI-based control design methods with no safety certification. It also moves away from existing safe control design approaches that perform pointwise optimization and are thus myopic. Safety assurance requires satisfying a control barrier function (CBF), which might be in conflict with the performance-driven Lyapunov solution to the Bellman equation arising in each iteration of the PI. Therefore, a new development is required to robustly certify the safety of an improved policy at each iteration of the PI. The proposed SR-PI algorithm unifies performance guarantee (provided by a Bellman inequality) with safety guarantee (provided by a robust CBF) at each iteration. The Bellman inequality resembles the satisficing decision making framework and parameterizes the sacrifice on the performance with an aspiration level when there is a conflict with safety. This aspiration level is optimized at each iteration to minimize the sacrifice on the performance. It is shown that the presented satisficing control policies obtained at each iteration of the SR-PI guarantees robust safety and performance. Robust stability is also guaranteed when there is no conflict with safety. Sum of squares (SOS) program is employed to implement the proposed SR-PI algorithm iteratively. Finally, numerical simulations are carried out to illustrate the proposed satisficing control framework.
M{\o}ller scattering in $2 + 1$ of generalized quantum electrodynamics in the heisenberg picture

In this paper, we investigate from the framework of generalized electrodynamics the differential cross section of the electron-electron scattering process $e^- e^- \rightarrow e^- e^-$, i.e., Moller scattering, in $(2+1)$ dimensions in the Heisenberg picture. To this goal, one starts within the stable and unitary framework of planar generalized electrodynamics, instead of Maxwell one. We argue the Haag's theorem strongly suggests the study of the differential cross section in the Heisenberg representation. Afterward, we explore the influence of Podolsky mass cutoff and calculate the differential cross section considering data based on condensed matter systems.
Dynamo Saturation through the Latitudinal Variation of Bipolar Magnetic Regions in the Sun

Observations of the solar magnetic cycle showed that the amplitude of the cycle did not grow all the time in the past. Thus, there must be a mechanism to halt the growth of the magnetic field in the Sun. We demonstrate a recently proposed mechanism for this under the Babcock–Leighton dynamo framework, which is believed to be the most promising paradigm for the generation of the solar magnetic field at present. This mechanism is based on the observational fact that the stronger solar cycles produce bipolar magnetic regions (BMRs) at higher latitudes and thus have higher mean latitudes than the weaker ones. We capture this effect in our three-dimensional Babcock–Leighton solar dynamo model and show that when the toroidal magnetic field tries to grow, it produce BMRs at higher latitudes. The BMRs at higher latitudes generate a less poloidal field, which consequently limits the overall growth of the magnetic field in our model. Thus, our study suggests that the latitudinal variation of BMRs is a potential mechanism for limiting the magnetic field growth in the Sun.
Conservative discontinuous Galerkin scheme of a gyro-averaged Dougherty collision operator

A conservative discontinuous Galerkin scheme for a non-linear Dougherty collision operator in full-f long-wavelength gyrokinetics is presented. Analytically this model operator has the advective-diffusive form of Fokker-Planck operators, it has a non-decreasing entropy functional, and conserves particles, momentum and energy. Discretely these conservative properties are maintained exactly as well, independent of numerical resolution. In this work the phase space discretization is performed using a novel version of the discontinuous Galerkin scheme, carefully constructed using concepts of weak equality and recovery. Discrete time advancement is carried out with an explicit time-stepping algorithm, whose stability limits we explore. The formulation and implementation within the long-wavelength gyrokinetic solver of Gkeyll are validated with relaxation tests, collisional Landau-damping benchmarks and the study of 5D gyrokinetic turbulence on helical, open field lines.
On the use of local structural properties for improving the efficiency of hierarchical community detection methods

Community detection is a fundamental problem in the analysis of complex networks. It is the analogue of clustering in network data mining. Within community detection methods, hierarchical algorithms are popular. However, their iterative nature and the need to recompute the structural properties used to split the network (i.e. edge betweenness in Girvan and Newman's algorithm), make them unsuitable for large network data sets. In this paper, we study how local structural network properties can be used as proxies to improve the efficiency of hierarchical community detection while, at the same time, achieving competitive results in terms of modularity. In particular, we study the potential use of the structural properties commonly used to perform local link prediction, a supervised learning problem where community structure is relevant, as nodes are prone to establish new links with other nodes within their communities. In addition, we check the performance impact of network pruning heuristics as an ancillary tactic to make hierarchical community detection more efficient
Privacy in targeted advertising: A survey

Targeted advertising has transformed the marketing trend for any business by creating new opportunities for advertisers to reach prospective customers by delivering them personalised ads using an infrastructure of a variety of intermediary entities and technologies. The advertising and analytics companies collect, aggregate, process and trade a rich amount of user's personal data, which has prompted serious privacy concerns among individuals and organisations. This article presents a detailed survey of privacy risks including the information flow between advertising platform and ad/analytics networks, the profiling process, the advertising sources and criteria, the measurement analysis of targeted advertising based on user's interests and profiling context and ads delivery process in both in-app and in-browser targeted ads. We provide detailed discussion of challenges in preserving user privacy that includes privacy threats posed by the advertising and analytics companies, how private information is extracted and exchanged among various advertising entities, privacy threats from third-party tracking, re-identification of private information and associated privacy risks, in addition to, overview data and tracking sharing technologies. Following, we present various techniques for preserving user privacy and a comprehensive analysis of various proposals founded on those techniques and compare them based on the underlying architectures, the privacy mechanisms and the deployment scenarios. Finally we discuss some potential research challenges and open research issues.
Coverage Probability and Ergodic Capacity of Intelligent Reflecting Surface-Enhanced Communication Systems

This letter studies the performance of a single-input single-output (SISO) system enhanced by the assistance of an intelligent reflecting surface (IRS), which is equipped with a finite number of elements under Rayleigh fading channels. From the instantaneous channel capacity, we compute a closed-form expression of the coverage probability as a function of statistical channel information only. A scaling law of the coverage probability and the number of phase shifts is further obtained. The ergodic capacity is derived, then a simple upper bound to simplify matters of utilizing the symbolic functions and can be applied for a long period of time. Numerical results manifest the tightness and effectiveness of our closed-form expressions compared with Monte-Carlo simulations.
Dynamic polarization and plasmons in Kekulé-patterned graphene: Signatures of broken valley degeneracy

The dynamic polarization for kekule-patterned graphene is studied within the Random Phase Approximation (RPA). It is shown how the breaking of the valley degeneracy by the lattice modulation is manifested through the dielectric spectrum, the plasmonic dispersion, the static screening and the optical conductivity. The valley-dependent splitting of the Fermi velocities due to the kekule distortion leads to a similar splitting in the dielectric spectrum of graphene, introducing new characteristic frequencies, which are given in terms of the valley-coupling amplitude. The valley coupling also splits the plasmonic dispersion, introducing a second branch in the Landau damping region. Finally, the signatures of the broken valley degeneracy in the optical conductivity are studied. The characteristic step-like spectrum of graphene is split into two half steps due to the onset of absorption in each valley occurring at different characteristic frequencies. Also, it was found an absorption phenomenon where a resonance peak related to intervalley transport emerges at a "beat frequency", determined by the difference between the characteristic frequencies of each valley. Some of these mechanisms are expected to be present in other space-modulated 2D materials and suggest how optical or electrical response measurements can be suitable to detect spatial modulation.
An ALMA Survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS Field: The Far-infrared/Radio Correlation for High-redshift Dusty Star-forming Galaxies

We study the radio properties of 706 submillimeter galaxies (SMGs) selected at 870 μm with the Atacama Large Millimeter Array from the SCUBA-2 Cosmology Legacy Survey map of the Ultra Deep Survey field. We detect 273 SMGs at >4σ in deep Karl G. Jansky Very Large Array 1.4 GHz observations, of which a subset of 45 SMGs are additionally detected in 610 MHz Giant Metre-Wave Radio Telescope imaging. We quantify the far-infrared/radio correlation (FIRRC) through parameter qIR, defined as the logarithmic ratio of the far-infrared and radio luminosity, and include the radio-undetected SMGs through a stacking analysis. We determine a median qIR = 2.20 ± 0.03 for the full sample, independent of redshift, which places these z ∼ 2.5 dusty star-forming galaxies 0.44 ± 0.04 dex below the local correlation for both normal star-forming galaxies and local ultra-luminous infrared galaxies (ULIRGs). Both the lack of redshift evolution and the offset from the local correlation are likely the result of the different physical conditions in high-redshift starburst galaxies, compared to local star-forming sources. We explain the offset through a combination of strong magnetic fields (B ≳ 0.2 mG), high interstellar medium (ISM) densities and additional radio emission generated by secondary cosmic rays. While local ULIRGs are likely to have similar magnetic field strengths, we find that their compactness, in combination with a higher ISM density compared to SMGs, naturally explains why local and high-redshift dusty star-forming galaxies follow a different FIRRC. Overall, our findings paint SMGs as a homogeneous population of galaxies, as illustrated by their tight and nonevolving far-infrared/radio correlation.
Using mobile-device sensors to teach students error analysis

Science students must deal with the errors inherent to all physical measurements and be conscious of the need to expressvthem as a best estimate and a range of uncertainty. Errors are routinely classified as statistical or systematic. Although statistical errors are usually dealt with in the first years of science studies, the typical approaches are based on manually performing repetitive observations. Our work proposes a set of laboratory experiments to teach error and uncertainties based on data recorded with the sensors available in many mobile devices. The main aspects addressed are the physical meaning of the mean value and standard deviation, and the interpretation of histograms and distributions. The normality of the fluctuations is analyzed qualitatively comparing histograms with normal curves and quantitatively comparing the number of observations in intervals to the number expected according to a normal distribution and also performing a Chi-squared test. We show that the distribution usually follows a normal distribution, however, when the sensor is placed on top of a loudspeaker playing a pure tone significant differences with a normal distribution are observed. As applications to every day situations we discuss the intensity of the fluctuations in different situations, such as placing the device on a table or holding it with the hands in different ways. Other activities are focused on the smoothness of a road quantified in terms of the fluctuations registered by the accelerometer. The present proposal contributes to gaining a deep insight into modern technologies and statistical errors and, finally, motivating and encouraging engineering and science students.
Swift/BAT and RXTE/ASM Observations of the 35 day X-Ray Cycle of Hercules X-1

Swift/BAT and RXTE/ASM observations have monitored the X-ray binary system Her X-1 for approximately 14.5 yr each, and both were monitoring Her X-1 for a period of ∼5.5 yr. Here we study the 35 day cycle using these observations. Using a cross-correlation method we find the times of peaks of the 35 day cycles for ∼150 cycles observed by Swift/BAT and ∼150 cycles observed by RXTE/ASM. These cycles include ∼60 observed with both instruments. The noise level of the RXTE/ASM measurements is larger than that of Swift/BAT, resulting in larger uncertainty in peak times. The distribution of 35 day cycle lengths can be fit with a Gaussian with mean 34.79 days and σ of 1.1 days. The distribution of orbital phases of 35 day cycle peaks is well fit by a uniform distribution, with 76% of the cycles, plus a Gaussian distribution peaked at orbital phase ∼0.5, with 24% of the cycles. We construct the long-term average 35 day lightcurve in the 15–50 keV band from Swift/BAT, and in the 2–12 keV band from RXTE/ASM. The high-energy band shows more variability in the short high state and the low-energy band shows more variability in the main high state. This is consistent with a precessing accretion disk model as the cause of the 35 day cycle.
A new high resolution code called RAMSES

A new N-body and hydrodynamical code, called RAMSES, is presented. It has been designed to study structure formation in the universe with high spatial resolution. The code is based on Adaptive Mesh Refinement (AMR) technique, with a tree-based data structure allowing recursive grid refinements on a cell-by-cell basis. The N-body solver is very similar to the one developed for the ART code (Kravtsov et al. 1997), with minor differences in the exact implementation. The hydrodynamical solver is based on a second-order Godunov method, a modern shock-capturing scheme known to compute accurately the thermal history of the fluid component. The accuracy of the code is carefully estimated using various test cases, from pure gas dynamical tests to cosmological ones. The specific refinement strategy used in cosmological simulations is described, and potential spurious effects associated with shock waves propagation in the resulting AMR grid are discussed and found to be negligible. Results obtained in a large N-body and hydrodynamical simulation of structure formation in a low density ΛCDM universe are reported, with 256 particles and 4.1 × 10 cells in the AMR grid, reaching a formal resolution of 8192. A convergence analysis of different quantities, such as dark matter density power spectrum, gas pressure power spectrum and individual haloe temperature profiles, shows that numerical results are converging down to the actual resolution limit of the code, and are well reproduced by recent analytical predictions in the framework of
Comparing the Outcomes of "Pre-CURE" Compared to Inquiry-Based Introductory Biology Labs.

Course-based undergraduate research experiences (CUREs) are increasing being taught to undergraduates across institutions and topics and offer an opportunity for more students to participate in authentic research. There are many types of “CUREs” with varying degrees of including all five elements identified by Auchincloss et al. (2014) as defining a CURE course. Even when authentic research labs do not include all the elements of a CURE, they still provide students an opportunity to engage in the process of science and could be an important transition from inquirystyle labs to full CURE labs. In this paper, we call labs that provide research experiences, yet may include lowerstakes, non-iterative or narrowly relevant results “pre-CURE” labs. We sought to assess if students were developing a better understanding of experimental design and scientific argumentation in a pre-CURE vs. a guided-inquiry version of the same introductory biology lab, as evidenced by scientific paper writing assignments. Students in guided-inquiry labs performed better on argumentation themes (p=0.01549) in their lab reports, conceivably because they had narrower variable selection. However, students learned more about experimental design in the pre-CURE course (p=1.77-12). Particularly because the pre-CURE gave the students the opportunity to fail by allowing them to design experiments that did not yield results.
AN IMPROVEMENT OF RESERVOIR RULE CURVES FOR INCREASING STORAGE CAPACITY

Reservoir rule curves are necessary guidelines for both flood and drought control in operating multipurpose reservoirs. As sure storage enough water for next dry season controlling by rule curves with the maximum storage at the end of rainy season. This study applied the conditional genetic algorithm and reservoir simulation model to improve reservoir rule cures for storing the highest capacity at the end of rainy season. Historic inflow data and future inflow data under a climate change scenario were used in searching procedure. Three large reservoirs in the northeast region of Thailand were considered for this study-Ubolrat reservoir, Lampao reservoir and Nam Oon reservoir. The future inflow and the synthetic inflow were used to evaluate the efficiency of the newly obtained rule curves. The situations of water shortage and excess water as well as the stored water at the end of the wet season were used for describing the performance. The results showed that the optimal rule curves with objective function of maximum storage at the end of wet season can provide more stored water at the end of wet season than when other rule curves are used.The obtained rule curves can control the maximum storage at the end of rainy season and mitigate situations of water shortage and water excess better than the current rule curves.
Online Appendix: Similar Literature in Other Fields

Because the Heckman two-step method originated in the field of Economics, we examined recent papers in the Journal of Economics and Management Strategy (JEMS) to learn whether a Strategy journal more closely tied to Economics used the Heckman two-step method more correctly. Using the same technique to find cites of Heckman (1979) between 1995 and 2016, we were surprised to find that only four papers in JEMS use the Heckman two-step method. To compare relative emphasis on different techniques, we used the database at Wiley Online to conduct a keyword search of the four journals analyzed above and of JEMS. The results appear in Table A1. First, as we expected, only 13% of JEMS articles that mention endogeneity also mention Heckman; the comparable figures for SMJ, ASQ, MS, and OS are 25%, 19%, 14%, and 19% respectively. Thus JEMS seems to be using the Heckman two-step method less when encountering endogeneity. Second, we find that JEMS contributors employ other instrumental-variable approaches: 68% of articles in JEMS that mention endogeneity also mention instrument, as compared to 51%, 44%, 65%, and 68% respectively for the other four journals. Finally, articles that name endogeneity and Heckman account for a smaller proportion of those that mention instrument and endogeneity in JEMS, at 18%, than in the other four journals at 49%, 44%, 22% and 27% respectively. INSERT Table A1 In order to pinpoint the differences in techniques, we further analyzed the sub-sample of JEMS articles that mention both instrument and endogeneity for common trends. Of these 65 papers, 14 explicitly use two-stage least-squares, 26 use instrumental variables in OLS, and three use the Generalized Method of Moments with instruments. Furthermore, ten explicitly explain why instrumental-variable approaches would be inappropriate for their setting or their data. Of the papers that use instrumental-variable approaches, all but five (two of which explicitly use the technique as a robustness check) either employ a statistical technique or economic intuition to justify the use of the instruments; three of the articles also use the Heckman two-step method. This analysis demonstrates that journals focused on the economics literature within the Strategy field make less use of the Heckman two-step method and more use of other instrumental-variables techniques accompanied by statistical tests for the validity of the instruments. Because the Heckman two-step method was introduced in the Economics literature earlier and was used widely after its introduction, its weaknesses were first identified and discussed in that literature; other fields seem to have been slower to follow suit. Recently, other fields that took up the Heckman two-step method with comparable fervor have begun to recognize the need for certain assumptions to be met. For example, Lennox,
Experimental investigation of the return flow instability in magnetized spherical Couette flows

We conduct magnetic spherical Couette (MSC) flow experiments in the return flow instability regime with GaInSn as the working fluid, and the ratio of the inner to the outer sphere radii $r_{\rm i}/r_{\rm o} = 0.5$, the Reynolds number ${\rm Re} = 1000$, and the Hartmann number ${\rm Ha} \in [27.5,40]$. Rotating waves with different azimuthal wavenumbers $m \in \{2, 3, 4\}$ manifest in certain ranges of ${\rm Ha}$ in the experiments, depending on whether the values of ${\rm Ha}$ were fixed or varied from different initial values. These observations demonstrate the multistability of rotating waves, which we attribute to the dynamical system representing the state of the MSC flow tending to move along the same solution branch of the bifurcation diagram when ${\rm Ha}$ is varied. In experiments with both fixed and varying ${\rm Ha}$, the rotation frequencies of the rotating waves are consistent with the results of nonlinear stability analysis. A brief numerical investigation shows that differences in the azimuthal wavenumbers of the rotating waves that develop in the flow also depend on the azimuthal modes that are initially excited.