Quantifying the value of structural monitoring for decision making

A life-cycle approach to infrastructure design and management involves decisions pertaining to operation, maintenance, intervention, and rapid response measures. Such an approach may only be conceived when formulated on the basis of observations during the life-cycle of these systems. Structural Health Monitoring (SHM) offers a tool to such an end, with sensors employed to generate information on the state of structural systems, which may then be exploited to derive performance indicators. A fundamental, practical question regarding monitoring of structural systems is however the quantification of any gains, monetary or otherwise, for infrastructure owners if they choose to install a monitoring system to their structures, in place of, or in addition to, other available choices, such as structural inspection visits. This essentially comprises a Value of Structural Health Monitoring (VoSHM) problem, which poses important mathematical and computational challenges related to several infrastructure system uncertainties, stochastic observations and their Value of Information (VoI), and any uncertain action outcomes. In this work, we implement optimal stochastic control approaches for infrastructure management in the form of Partially Observable Markov Decision Processes (POMDPs), which inherently possess the notion of the VoI into their formulation and, in fact, automatically utilize it at every decision step for decision-making. In addition, we show that based on POMDPs the VoSHM can be efficiently estimated, allowing for informative decisions by the structural owner, based on quantitative metrics in relation to the expected benefits of the SHM system. A representative application is shown in this regard for a multi-component engineering system, showcasing the wide applicability and effectiveness of the suggested approach and its practical merits.This material is based upon work supported by the U.S. National Science Foundation under CAREER Grant No. 1751941

Lithospheric electrical structure across the Bangong-Nujiang Suture in northern tibet revealed by magnetotelluric

Competing hypotheses have been proposed to explain the subduction polarity of the Bangong-Nujiang Tethyan Ocean and the formation of the high-conductivity anomaly beneath the Qiangtang terrane. However, the lithospheric architecture of the northern Tibetan Plateau is still poorly understood due to inhospitable environments and topography. Therefore, in the winter of 2021, a 440 km long, SN-trending broadband magnetotelluric (MT) profile was recorded in northern Tibet to detect its regional lithospheric structure. The nonlinear conjugate gradients algorithm is conducted to invert the individual TM mode data. A reliable 2D electrical model was obtained by ablation processing and analysis of broadband magnetotelluric data to test the lithospheric electrical structure and dynamics between the northern Lhasa and Qiangtang terranes. The inversion results reveal the lithospheric structure at a depth of 100 km in northern Tibet, which synthesizes geological, geochemical and deep seismic reflection evidence and firmly identifies that the trace of the south-dipping conductor mainly resulted from the southward subduction of the Bangong-Nujiang Tethyan Ocean under the Lhasa terrane and the trace of the north-dipping conductor likely due to the northward subduction of the Bangong-Nujiang Tethyan Ocean under the Qiangtang terrane. In addition, the magnetotelluric profile also images a high-conductivity lithospheric-scale anticline beneath the central Qiangtang terrane, which may correspond to the upwelling of postcollisional magmatism triggered by northward subduction of the Bangong-Nujiang Tethyan Ocean under the Qiangtang terrane, aqueous fluid and/or partial melting

Misregulation of Alternative Splicing in a Mouse Model of Rett Syndrome

Mutations in the human MECP2 gene cause Rett syndrome (RTT), a severe neurodevelopmental disorder that predominantly affects girls. Despite decades of work, the molecular function of MeCP2 is not fully understood. Here we report a systematic identification of MeCP2-interacting proteins in the mouse brain. In addition to transcription regulators, we found that MeCP2 physically interacts with several modulators of RNA splicing, including LEDGF and DHX9. These interactions are disrupted by RTT causing mutations, suggesting that they may play a role in RTT pathogenesis. Consistent with the idea, deep RNA sequencing revealed misregulation of hundreds of splicing events in the cortex of Mecp2 knockout mice. To reveal the functional consequence of altered RNA splicing due to the loss of MeCP2, we focused on the regulation of the splicing of the flip/flop exon of Gria2 and other AMPAR genes. We found a significant splicing shift in the flip/flop exon toward the flop inclusion, leading to a faster decay in the AMPAR gated current and altered synaptic transmission. In summary, our study identified direct physical interaction between MeCP2 and splicing factors, a novel MeCP2 target gene, and established functional connection between a specific RNA splicing change and synaptic phenotypes in RTT mice. These results not only help our understanding of the molecular function of MeCP2, but also reveal potential drug targets for future therapies

Transdifferentiation of lung adenocarcinoma in mice with Lkb1 deficiency to squamous cell carcinoma

Lineage transition in adenocarcinoma (ADC) and squamous cell carcinoma (SCC) of non-small cell lung cancer, as implicated by clinical observation of mixed ADC and SCC pathologies in adenosquamous cell carcinoma, remains a fundamental yet unsolved question. Here we provide in vivo evidence showing the transdifferentiation of lung cancer from ADC to SCC in mice: Lkb1-deficient lung ADC progressively transdifferentiates into SCC, via a pathologically mixed mAd-SCC intermediate. We find that reduction of lysyl oxidase (Lox) in Lkb1-deficient lung ADC decreases collagen disposition and triggers extracellular matrix remodelling and upregulates p63 expression, a SCC lineage survival oncogene. Pharmacological Lox inhibition promotes the transdifferentiation, whereas ectopic Lox expression significantly inhibits this process. Notably, ADC and SCC show differential responses to Lox inhibition. Collectively, our findings demonstrate the de novo transdifferentiation of lung ADC to SCC in mice and provide mechanistic insight that may have important implications for lung cancer treatment

Baichuan 2: Open Large-scale Language Models

Large language models (LLMs) have demonstrated remarkable performance on a variety of natural language tasks based on just a few examples of natural language instructions, reducing the need for extensive feature engineering. However, most powerful LLMs are closed-source or limited in their capability for languages other than English. In this technical report, we present Baichuan 2, a series of large-scale multilingual language models containing 7 billion and 13 billion parameters, trained from scratch, on 2.6 trillion tokens. Baichuan 2 matches or outperforms other open-source models of similar size on public benchmarks like MMLU, CMMLU, GSM8K, and HumanEval. Furthermore, Baichuan 2 excels in vertical domains such as medicine and law. We will release all pre-training model checkpoints to benefit the research community in better understanding the training dynamics of Baichuan 2.Comment: Baichuan 2 technical report. Github: https://github.com/baichuan-inc/Baichuan

Effects of Pre-Freezing Prior to Drying upon Some Physical and Mechanical Properties of Eucalyptus urophylla × Eucalyptus grandis Wood

To investigate the effect of pre-freezing treatment on the shrinkage properties and discoloration of Eucalyptus urophylla × Eucalyptus grandis wood, E. urophylla × E. grandis wood samples were treated by pre-freezing at -20 and -40 °C for 72 h and then dried to reach equilibrium moisture content at 12% and 8%, respectively. Color changes were measured by colorimeter and evaluated by diffuse reflectance visible (DRV) spectrometry; mechanical properties were also tested. The results showed that the shrinkage of Eucalyptus wood samples decreased after being pre-frozen, and the overall color change ΔE* increased by 6.11 when the treatment temperature changed from minus 20 to -40 °C. Absorption (ΔK/S) spectra in the range of 450 to 740 nm of the treatment samples exhibited flat-lined, which suggests that the color of wood stabilizes after being pre-frozen and dried. The tensile, compression and bending strengths decreased 4.74, 6.05, 1.18 after pre-freezing treatment at -40 °C, respectively. Pre-freezing treatment at -20 °C is better than that at -40 °C for improving the drying properties of E. urophylla × E. grandis wood

Improved Chimpanzee Search Algorithm with Multi-Strategy Fusion and Its Application

An improved chimpanzee optimization algorithm incorporating multiple strategies (IMSChoA) is proposed to address the problems of initialized population boundary aggregation distribution, slow convergence speed, low precision, and proneness to fall into local optimality of the chimpanzee search algorithm. Firstly, the improved sine chaotic mapping is used to initialize the population to solve the population boundary aggregation distribution problem. Secondly, a linear weighting factor and an adaptive acceleration factor are added to join the particle swarm idea and cooperate with the improved nonlinear convergence factor to balance the global search ability of the algorithm, accelerate the convergence of the algorithm, and improve the convergence accuracy. Finally, the sparrow elite mutation and Bernoulli chaos mapping strategy improved by adaptive change water wave factor are added to improve the ability of individuals to jump out of the local optimum. Through the comparative analysis of benchmark functions seeking optimization and the comparison of Wilcoxon rank sum statistical test seeking results, it can be seen that the IMSChoA optimization algorithm has stronger robustness and applicability. Further, the IMSChoA optimization algorithm is applied to two engineering examples to verify the superiority of the IMSChoA optimization algorithm in dealing with mechanical structure optimization design problems

Monolithically Integrated Optoelectronic Receivers Implemented in 0. 25μm MS/RF CMOS

A monolithically integrated optoelectronic receiver is presented. A silicon-based photo-diode and receiver circuits are integrated on identical substrates in order to eliminate the parasitics induced by hybrid packaging. Implemented in the present deep sub-micron MS/RF （mixed signal, radio frequency） CMOS,this monolithically OEIC takes advantage of several new features to improve the performance of the photo-diode and eventually the whole OEIC