Implementing the multimodel generalized beta estimator in stata and its application

The multimodel generalized beta estimator (MGBE) described by von Hippel, Scarpino and Hola (2014) provides researchers with an improved way to estimate inequality from binned incomes. To extend the application of MGBE, the mgbe command is developed in Stata. In this report, the implementation and performance of mgbe are discussed.Statistic

Probing dark energy with large-scale galaxy clustering: from instrumentation to simulation

In the standard paradigm of cosmology, everything we observe now originated from initial quantum fluctuations in a small smooth region, which were frozen in during inflation and became primordial density perturbations on large classical scales. Under gravitational collapse, the overdensities seeded the formation of stars and galaxies. Mapping the large-scale structure of the universe at the Cosmic Frontier is a promising experimental avenue which will address in the next decade several pressing open questions in cosmology and particle physics, most notably the accelerating cosmic expansion. The observed distribution of galaxies and quasars traces the underlying matter density field and contains a wealth of information from signatures of primordial conditions to the background evolution rate. The Dark Energy Spectroscopic Instrument (DESI) is a next-generation, Stage IV dark energy experiment that will measure the expansion history of the universe through baryon acoustic oscillations and the growth of structure through redshift-space distortions with unprecedented precision. Ground-based at the Kitt Peak National Observatory, DESI features a new 8 deg² field-of-view corrector, 5000 robotically-actuated fibre positioners, and ten fibre-fed spectrographs. The 5-year survey beginning in 2020 will measure the spectra of 35 million galaxies and quasars up to redshift z ~ 3.5 in the 360 nm to 980 nm wavelength range, covering 14000 deg² of the sky. With an order of magnitude improvement over previous redshift surveys, DESI will place tight constraints on the dark energy equation of state, modified gravity, the existence of extra light species, neutrino masses, and models of inflation. ProtoDESI was a proof of concept commissioned in 2016 to mitigate the risks associated with DESI's challenging instrument design and precision requirements. Its simplified focal plane instrument housed 3 fibre positioners and a fibre photometry camera in place of spectrographs. ProtoDESI was successful as the first on-sky technology demonstration for DESI. For the official DESI focal plane instrument, the fibre positioning accuracy and, ultimately, the success of DESI, are grounded upon the stringent specifications of the focal plate structure (FPS) which directly holds the positioners. The FPS parts, consisting of ten focal plate petals (FPPs) and a focal plate ring, were fabricated with the required tolerances, comprehensively inspected, and aligned with appropriate shims and gauge blocks to ensure minimal loss of photons at the fibre tips. Adopting a coordinate measurement machine-based approach, we projected the fibre injection efficiency by measuring hardware features and modelling geometric transformations and fibre optics. The as-aligned, total root-mean-square optical throughput for 6168 positioner holes of 12 production FPPs (including two spares) is 99.88% ± 0.12%, well above the 99.5% project requirement. Finally, observations of galaxy clustering cannot be properly understood alone without accompanying theoretical motivations and numerical simulations in parallel. Cosmological N-body simulations have become indispensable for designing survey strategies, developing analysis methods, and making theoretical predictions. We quantify the shifts of the acoustic scale potentially resulting from galaxy clustering bias, which constitutes an increasingly significant source of theoretical systematics in distance measurements with the standard ruler. Utilising mock catalogues based on generalised halo occupation population of high-accuracy Abacus simulations in the largest volume to date for such tests, 48h⁻¹Gpc³, we find a 0.3% shift in the line-of-sight acoustic scale for one variation in the satellite galaxy population and a 0.7% shift for an extreme level of velocity bias of the central galaxies, while other models tested are consistent with zero shift at the 0.2% level after reconstruction. We note that these bias models produce sizeable and likely distinguishable changes at small scales that correlate with the shifts

EDMSound: Spectrogram Based Diffusion Models for Efficient and High-Quality Audio Synthesis

Audio diffusion models can synthesize a wide variety of sounds. Existing models often operate on the latent domain with cascaded phase recovery modules to reconstruct waveform. This poses challenges when generating high-fidelity audio. In this paper, we propose EDMSound, a diffusion-based generative model in spectrogram domain under the framework of elucidated diffusion models (EDM). Combining with efficient deterministic sampler, we achieved similar Fr\'echet audio distance (FAD) score as top-ranked baseline with only 10 steps and reached state-of-the-art performance with 50 steps on the DCASE2023 foley sound generation benchmark. We also revealed a potential concern regarding diffusion based audio generation models that they tend to generate samples with high perceptual similarity to the data from training data. Project page: https://agentcooper2002.github.io/EDMSound/Comment: Accepted at NeurIPS Workshop: Machine Learning for Audio (Camera Ready

Focal Plate Structure Alignment of the Dark Energy Spectroscopic Instrument

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the Baryon Acoustic Oscillation (BAO) technique. The spectra of 35 million galaxies and quasars over $14000 \,\text{deg}^2$ will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 robotically positioned optic fibres. The fibres in turn feed ten broadband spectrographs. Proper alignment of focal plate structure, mainly consisting of a focal plate ring (FPR) and ten focal plate petals (FPP), is crucial in ensuring minimal loss of light in the focal plane. A coordinate measurement machine (CMM) metrology-based approach to alignment requires comprehensive characterisation of critical dimensions of the petals and the ring, all of which were 100% inspected. The metrology data not only served for quality assurance (QA), but also, with careful modelling of geometric transformations, informed the initial choice of integration accessories such as gauge blocks, pads, and shims. The integrated focal plate structure was inspected again on a CMM, and each petal was adjusted according to the updated focal plate metrology data until all datums were extremely close to nominal positions and optical throughput nearly reached the theoretically best possible value. This paper presents our metrology and alignment methodology and complete results for twelve official DESI petals. The as-aligned, total RMS optical throughput for 6168 positioner holes of twelve production petals was indirectly measured to be $99.88 \pm 0.12 \%$, well above the 99.5% project requirement. The successful alignment fully demonstrated the wealth of data, reproducibility, and micron-level precision made available by our CMM metrology-based approach.Comment: 17 pages, 10 figures, 3 table

Extracted power optimization of hybrid wind-wave energy converters array layout via enhanced snake optimizer

In recent years, wind energy and wave energy are widely concerned as highly developmental clean energy alternatives to traditional energy sources. From the perspective of cost reduction and power output enhancement, in this study, a V27-225 kW wind turbine and wave energy converter are combined to construct a hybrid wind-wave energy converters (HWWEC), which greatly improves the power generation and operation stability. The optimization of wind-wave energy layout that involves strategically placing wave energy devices can directly influence the energy output of the whole system. To enhance the overall power generation efficiency, the optimal array configuration becomes a challenging but also promising solution regarding this concern. To optimize the array configuration that is composed of multiple HWWECS, this study develops an enhanced snake optimizer (ESO) based optimization scheme including chaotic initialization, asynchronous learning factors, and levy flight, which shows strong optimum searching ability while avoiding falling into local optimums. Simulation results under various case studies of three-line WECs consisting of three, six, and twelve buoys indicate that the ESO achieves the highest absorption power compared to other algorithms, particularly, the output power achieved by ESO is 144.337 kW higher than that obtained by the original SO

The DESI Sky Continuum Monitor System

The Dark Energy Spectroscopic Instrument (DESI) is an ongoing spectroscopic survey to measure the dark energy equation of state to unprecedented precision. We describe the DESI Sky Continuum Monitor System, which tracks the night sky brightness as part of a system that dynamically adjusts the spectroscopic exposure time to produce more uniform data quality and to maximize observing efficiency. The DESI dynamic exposure time calculator (ETC) will combine sky brightness measurements from the Sky Monitor with data from the guider system to calculate the exposure time to achieve uniform signal-to-noise ratio (SNR) in the spectra under various observing conditions. The DESI design includes 20 sky fibers, and these are split between two identical Sky Monitor units to provide redundancy. Each Sky Monitor unit uses an SBIG STXL-6303e CCD camera and supports an eight-position filter wheel. Both units have been completed and delivered to the Mayall Telescope at the Kitt Peak National Observatory. Commissioning results show that the Sky Monitor delivers the required performance necessary for the ETC.Comment: 9 pages, 7 figures, 1 tabl

The Clustering of DESI-like Luminous Red Galaxies Using Photometric Redshifts

We present measurements of the redshift-dependent clustering of a DESI-like luminous red galaxy (LRG) sample selected from the Legacy Survey imaging dataset, and use the halo occupation distribution (HOD) framework to fit the clustering signal. The photometric LRG sample in this study contains 2.7 million objects over the redshift range of $0.4 < z < 0.9$ over 5655 deg$^2$. We have developed new photometric redshift (photo-$z$) estimates using the Legacy Survey DECam and WISE photometry, with $\sigma_{\mathrm{NMAD}} = 0.02$ precision for LRGs. We compute the projected correlation function using new methods that maximize signal-to-noise ratio while incorporating redshift uncertainties. We present a novel algorithm for dividing irregular survey geometries into equal-area patches for jackknife resampling. For a five-parameter HOD model fit using the MultiDark halo catalog, we find that there is little evolution in HOD parameters except at the highest redshifts. The inferred large-scale structure bias is largely consistent with constant clustering amplitude over time. In an appendix, we explore limitations of Markov chain Monte Carlo fitting using stochastic likelihood estimates resulting from applying HOD methods to N-body catalogs, and present a new technique for finding best-fit parameters in this situation. Accompanying this paper we have released the Photometric Redshifts for the Legacy Surveys (PRLS) catalog of photo-$z$'s obtained by applying the methods used in this work to the full Legacy Survey Data Release 8 dataset. This catalog provides accurate photometric redshifts for objects with $z < 21$ over more than 16,000 deg$^2$ of sky.Comment: 24 pages, 25 figures, published in MNRA

Inflation and Dark Energy from spectroscopy at z > 2

The expansion of the Universe is understood to have accelerated during two epochs: in its very first moments during a period of Inflation and much more recently, at z < 1, when Dark Energy is hypothesized to drive cosmic acceleration. The undiscovered mechanisms behind these two epochs represent some of the most important open problems in fundamental physics. The large cosmological volume at 2 < z < 5, together with the ability to efficiently target high-$z$ galaxies with known techniques, enables large gains in the study of Inflation and Dark Energy. A future spectroscopic survey can test the Gaussianity of the initial conditions up to a factor of ~50 better than our current bounds, crossing the crucial theoretical threshold of $\sigma(f_{NL}^{\rm local})$ of order unity that separates single field and multi-field models. Simultaneously, it can measure the fraction of Dark Energy at the percent level up to $z = 5$, thus serving as an unprecedented test of the standard model and opening up a tremendous discovery space