Robustifying and Boosting Training-Free Neural Architecture Search

Neural architecture search (NAS) has become a key component of AutoML and a standard tool to automate the design of deep neural networks. Recently, training-free NAS as an emerging paradigm has successfully reduced the search costs of standard training-based NAS by estimating the true architecture performance with only training-free metrics. Nevertheless, the estimation ability of these metrics typically varies across different tasks, making it challenging to achieve robust and consistently good search performance on diverse tasks with only a single training-free metric. Meanwhile, the estimation gap between training-free metrics and the true architecture performances limits training-free NAS to achieve superior performance. To address these challenges, we propose the robustifying and boosting training-free NAS (RoBoT) algorithm which (a) employs the optimized combination of existing training-free metrics explored from Bayesian optimization to develop a robust and consistently better-performing metric on diverse tasks, and (b) applies greedy search, i.e., the exploitation, on the newly developed metric to bridge the aforementioned gap and consequently to boost the search performance of standard training-free NAS further. Remarkably, the expected performance of our RoBoT can be theoretically guaranteed, which improves over the existing training-free NAS under mild conditions with additional interesting insights. Our extensive experiments on various NAS benchmark tasks yield substantial empirical evidence to support our theoretical results.Comment: Accepted by ICLR 2024. Code available at https://github.com/hzf1174/RoBo

Sealing of oil-gas reservoir caprock: Destruction of shale caprock by micro-fractures

The sealing ability of caprock is affected by many factors, such as cap thickness, displacement pressure, fracture development, and lithology of caprock. Shale is one of the ideal materials for oil and gas sealing cap formation due to its low porosity and permeability. Microfractures can destroy the sealing property of shale caprock. When buried deep enough, shale will change from toughness to brittleness. In general, the greater the brittleness of shale, the more developed the fractures will be. In areas with high tectonic stress, such as the anticline axis, syncline axis and stratum dip end, the strata stress is high and concentrated, and it is easier to generate fractures. When the stress state of the caprock changes, new micro-cracks are formed or previously closed cracks are re-opened, reducing the displacement pressure of the caprock. These micro-fractures are interconnected to form microleakage spaces, which reduces the sealing capacity of the caprock

Fine-Scale Three-Dimensional Characterization of a Reservoir Comprising Braided River Sand Bodies with a Complex Stacking Pattern in a Cratonic Basin

AbstractThe complex stacking pattern of braided river sand bodies in the cratonic basins results in a multilevel and multistage spatial distribution of reservoir units, which increases the difficulty of characterizing the spatial distribution pattern of reservoir parameters. Therefore, when characterizing the spatial regularity of this type of reservoir, it is necessary to consider the stacking pattern of the sand bodies to select the constraints. In this paper, the He 8 section of the Sulige 120 area in the Ordos Basin, China, is taken as an example. First, based on analysis of the development scale and genetic type of sand bodies in the area, four sand body stacking patterns and plan-view distribution patterns are identified. Second, a study on how to improve the accuracy of braided river sand body models is carried out, and a sand body model is established. Finally, a three-dimensional model of reservoir properties is established by using the sequential Gaussian simulation method under the constraint of the phase control model. The model results show that the three-dimensional model of the sand bodies established by the multipoint geostatistical method has better connectivity and is more suitable for constructing sand body models under complex sand body stacking conditions. The training images established by the target body method can clearly identify the boundary of the main channel of the braided river and solve the discontinuity of the sand body distribution. The reservoir model established under the constraint of the sand body model can effectively simulate the nonhomogeneity in the reservoir parameters, which can play a crucial role in accurately predicting the porosity and permeability distribution patterns of reservoirs with complex sand body stacking pattern. The present study provides a new idea for characterizing complexly stacked sand body reservoirs in a cratonic basin

Resveratrol Activated Sonic Hedgehog Signaling to Enhance Viability of NIH3T3 Cells in Vitro via Regulation of Sirt1

Background/Aims: Injuries of the brain and spinal cord result in the formation of glial (reactive gliosis) and fibrotic (formed by fibroblasts) scars. Recent studies have shown that the fibrotic scar was much more important for hindering regeneration after brain or spinal cord injury than the astrocytic scar. However, it has been given much less attention for effects and mechanism of fibroblasts during formation of the fibrotic scar. Resveratrol may be a potential anti-scarring agent in burn-related scarring and keloid fibroblasts. However, it is unclear whether and how resveratrol affects formation of the fibrotic scar after brain or spinal cord injury. Earlier studies have shown that the activated Shh signaling has anti-apoptosis, anti-oxidation, anti-inflammation properties. Moreover, resveratrol can activate the Shh signaling. However, it is unclear how resveratrol activates the Shh signaling. Resveratrol is a activator of Sirt1. It is unknown whether resveratrol activates the Shh signaling via Sirt1. Methods: NIH3T3 cells, a fibroblast cell line, were used as model cells and treated with drugs. Cell viability was assessed by Cell Counting Kit 8. The expressions and activity of Shh signaling pathway proteins were evaluated by immunocytochemistry and Western blotting. Transcriptional activity of Gli-1 was detected with Dual-Luciferase Reporter Gene Assay Kit. Results: Resveratrol, Sirt1 agonist STR1720 and recombinant mouse Shh protein, an activator of hedgehog signaling, enhanced the viability of NIH3T3 cells, promoted Smo to translocated to the primary cilia and Gli-1 entered into the nuclei from cytoplasm, and upregulated expressions of Shh, Ptc-1, Smo, and Gli-1 proteins, which can be reversed by Smo antagonist cyclopamine and Sirt1 antagonist Sirtinol. Additionally, resveratrol increased transcriptional activity of Gli-1. Conclusion: We indicate in the first time that it may be mediated by Sirt1 for resveratrol activating the Shh signaling to enhance viability of NIH3T3 cells, and Sirt1 may be a regulator for upstream of the Shh signaling pathway.This study provides a basis for further investigating effects and mechanism of resveratrol during the formation of fibrous scar after brain or spinal cord injury

Characterization of horn antenna loaded with CLL unit cell

YesIn this paper, a pyramidal horn antenna loaded with unit cell of metamaterial is proposed, designed and realized for L-band that including terrestrial digital audio broadcasting TDAB, GPS and GSM. The proposed antenna operates in the frequency range from 1.722 GHz to 1.931 GHz. The metamaterial is fabricated on a printed circuit board as Capacitive Loaded Loop (CLL). The work aims to exhibit the advantage of metamaterial loaded inside the horn antenna in terms of the gain enhancement of the radiation pattern and the resonant frequency shift towards lower frequency. The retrieval technique used show that the constitutive parameters of the unit cell as CLL have a zero index metamaterial (ZIM) from 1.34 GHz to 1.49 GHz and a near zero index of refraction from 1.495 GHz to 2 GHz, which is within the operating frequency of the horn antenna. The achieved results show that the total gain is improved over the frequency range. The simulation and the measurement are in good agreement

The Large High Altitude Air Shower Observatory (LHAASO) Science White Paper

The Large High Altitude Air Shower Observatory (LHAASO) project is a new generation multi-component instrument, to be built at 4410 meters of altitude in the Sichuan province of China, with the aim to study with unprecedented sensitivity the spec trum, the composition and the anisotropy of cosmic rays in the energy range between 10$^{12}$ and 10$^{18}$ eV, as well as to act simultaneously as a wide aperture (one stereoradiant), continuously-operated gamma ray telescope in the energy range between 10$^{11}$ and $10^{15}$ eV. The experiment will be able of continuously surveying the TeV sky for steady and transient sources from 100 GeV to 1 PeV, t hus opening for the first time the 100-1000 TeV range to the direct observations of the high energy cosmic ray sources. In addition, the different observables (electronic, muonic and Cherenkov/fluorescence components) that will be measured in LHAASO will allow to investigate origin, acceleration and propagation of the radiation through a measurement of energy spec trum, elemental composition and anisotropy with unprecedented resolution. The remarkable sensitivity of LHAASO in cosmic rays physics and gamma astronomy would play a key-role in the comprehensive general program to explore the High Energy Universe. LHAASO will allow important studies of fundamental physics (such as indirect dark matter search, Lorentz invariance violation, quantum gravity) and solar and heliospheric physics. In this document we introduce the concept of LHAASO and the main science goals, providing an overview of the project.Comment: This document is a collaborative effort, 185 pages, 110 figure

Conditional Correlations in the Returns on Oil Companies Stock Prices and Their Determinants

The identification of the forces that drive stock returns and the dynamics of their associated volatilities is a major concern in empirical economics and finance. This analysis is particularly relevant for determining optimal hedging strategies based on whether shocks to the volatilities of returns of oil companies stock prices, relevant stock market indexes and oil spot and futures prices are high or low, and positively or negatively correlated. This paper investigates the correlations of volatilities in the stock price returns and their determinants for the most important integrated oil companies, namely Bp (BP), Chevron-Texaco (CVX), Eni (ENI), Exxon-Mobil (XOM), Royal Dutch (RD) and Total-Fina Elf (TFE). We measure the actual co-risk in stock returns and their determinants within and between the different oil companies, using multivariate cointegration techniques in modelling the conditional mean, as well as multivariate GARCH models for the conditional variances. We focus first on the determinants of the market value of each company using the cointegrated VAR/VECM methodology. Then we specifiy the conditional variances of VECM residuals with the Constant Conditional Correlation (CCC) multivariate GARCH model of Bollerslev (1990) and the Dynamic Conditional Correlation (DCC) multivariate GARCH model of Engle (2002). The within and between DCC indicate low to high/extreme interdependence between the volatilities of companies' stock returns and the relevant stock market indexes or Brent oil prices

Adjustment of Land Use Structure Based on County-wide Economic Development: A Case Study of Changfeng County

On the basis of survey of current land use situation in Changfeng County, this paper analyzed land use structure, trend and environment of structural adjustment. Besides, it explored county-wide land use structure mode, namely, “division + indicator + policy”. Through reasonable distribution, it is expected to build proper land use structure framework, avoid passive situation of relying on policies simply, and bring into play stability keeping function of land use structure, so as to promote county-wide economic development, and bring into play county-wide lever function of rural transition areas