Time-dependent effects on dynamic properties of cable-stayed bridges

Structural health monitoring systems are often installed on bridges to provide assessments of the need for structural maintenance and repair. Damage or deterioration may be detected by observation of changes in bridge characteristics evaluated from measured structural responses. However, construction materials such as concrete and steel cables exhibit certain time-dependent behaviour, which also results in changes in structural characteristics. If these are not accounted for properly, false alarms may arise. This paper proposes a systematic and efficient method to study the time-dependent effects on the dynamic properties of cable-stayed bridges. After establishing the finite element model of a cable-stayed bridge taking into account geometric nonlinearities and time-dependent behaviour, long-term time-dependent analysis is carried out by time integration. Then the dynamic properties of the bridge after a certain period can be obtained. The effects of time-dependent behaviour of construction materials on the dynamic properties of typical cable-stayed bridges are investigated in detail.link_to_subscribed_fulltex

Efficient single-step time-dependent analysis of PC structures

This paper describes an efficient single-step method to predict the time-dependent behaviour of prestressed concrete (PC) structures due to concrete creep, concrete shrinkage and cable relaxation. A versatile tendon sub-element is first developed to model prestressing cables of arbitrary profiles. To enable accurate estimation of losses of cable forces, a new relaxation model is formulated based on the equivalent creep coefficient, which is verified to work not only in the case of intrinsic relaxation but also under various boundary conditions. An efficient single-step finite-element method is then devised for time-dependent analysis of PC structures considering creep, shrinkage and relaxation based on the age-adjusted elasticity modulus, shrinkage-adjusted elasticity modulus and relaxation-adjusted elasticity modulus respectively. The effects of creep, shrinkage and relaxation on the long-term performance of PC structures are investigated. The numerical results obtained indicate not only the accuracy of the method but also the significance of considering the interaction among various time-varying factors.published_or_final_versio

On four-point penalized Lagrange subdivision schemes

International audienceThis paper is devoted to the definition and analysis of new subdivision schemes called penalized Lagrange. Their construction is based on an originalreformulation for the construction of the coefficients of the mask associated to the classical $4$-points Lagrange interpolatory subdivision scheme: these coefficients can be formallyinterpreted as the solution of a linear system similar to the one resulting from the constrained minimization problem in Kriging theory which is commonly used for reconstruction in geostatistical studies. In sucha framework, the introduction in the formulation of a so-called error variance can be viewed as a penalization of the oscillations of the coefficients.Following this idea, we propose to penalize the $4$-points Lagrange system. This penalization transforms the interpolatory schemes into approximating ones with specific properties suitable for the subdivision of locallynoisy or strongly oscillating data. According to a so-called penalization vector, a family of schemes can be generated. A full theoretical study is first performed to analyze this new type of non stationary subdivision schemes. Then, in the framework of position dependant penalization vector, several numerical tests are provided to point out the efficiency of these schemes comparedto standard approaches

Topography affects grassland heterogeneity

Non-Peer ReviewedDetermining and monitoring ecosystem heterogeneity and biodiversity is important for grassland management and can be carried out through remote sensing such as satellite images. However, in rolling landscapes, biophysical properties of ecosystems, the indicators of heterogeneity and biodiversity are highly scale and location dependent and little research is reported on how topography affects biophysical properties of ecosystems quantitatively. The objective of this study is to examine how topography affects spatial biophysical variation using statistics and a wavelet approach in the mixed grassland ecosystem, Saskatchewan, Canada. Field leaf area index (LAI) was collected with an LAI-2000 instrument and topographical data were measured using a total station along five paralleled transects. Results showed that biophysical spatial variation is highly topography-controlled, and the wavelet approaches can be used to identify the spatial heterogeneity of a grassland ecosystem at different scales. This study suggests the potentials of using readily-available topography data to guide the ecosystems management and selection of the resolution of satellite images

A Close Look At The Driving Forces Of The Sino-Foreign International Joint Ventures

The current study employs measures developed for examining Sino-American international joint ventures (IJV) driving forces in transitional economies.  This research reports some significant differences of the IJV factors existing between mature economies and transitional economies. This study also proposes key driving forces to inform a Sino-American IJV in the Chinese context.  In addition, the current study explores the degree to which the above factors affect Sino-American IJV establishment in the context of contemporary Chinese conditions

Effects of matrine on JAK-STAT signaling transduction pathways in bleomycin-induced pulmonary fibrosis

The current study aims to investigate the effects of matrine on the JAK-STAT signaling transduction pathways in bleomycin (BLM)-induced pulmonary fibrosis (PF) and to explore its action mechanism. A total of 72 male C57BL/6 mice were randomized into the control, model, and treatment groups. PF models were established by instilling BLM intratracheally. The treatment group was given daily matrine through gastric lavage. Six mice were sacrificed in each group at 3, 7, 14, and28 days. The lung tissues were observed using hematoxylin-eosin staining. The expression of JAK, STAT1, and STAT3 was observed using immunohistochemistry and then determined using real-time polymerase chain reaction. Alveolitis and PF significantly improved in the treatment group compared with the model group (P < 0.05). The expression of JAK, STAT1, and STAT3 in the model group increased at day 7, peaked at day 14 and then decreased, but the expression was still higher than that in the control group at day 28 (P < 0.05). The three indices in the treatment group were significantly lower than those in the model group at any detection time point (P < 0.05). PF causes high expression of JAK, STAT1, and STAT3. Matrine exerts an anti-PF effect by inhibiting the JAK-STAT signaling transduction pathways.Key words: Pulmonary fibrosis, bleomycin, matrine, signaling transduction pathway

Supervision-by-Registration: An Unsupervised Approach to Improve the Precision of Facial Landmark Detectors

© 2018 IEEE. In this paper, we present supervision-by-registration, an unsupervised approach to improve the precision of facial landmark detectors on both images and video. Our key observation is that the detections of the same landmark in adjacent frames should be coherent with registration, i.e., optical flow. Interestingly, coherency of optical flow is a source of supervision that does not require manual labeling, and can be leveraged during detector training. For example, we can enforce in the training loss function that a detected landmark at framet-1 followed by optical flow tracking from framet-1 to framet should coincide with the location of the detection at framet. Essentially, supervision-by-registration augments the training loss function with a registration loss, thus training the detector to have output that is not only close to the annotations in labeled images, but also consistent with registration on large amounts of unlabeled videos. End-to-end training with the registration loss is made possible by a differentiable Lucas-Kanade operation, which computes optical flow registration in the forward pass, and back-propagates gradients that encourage temporal coherency in the detector. The output of our method is a more precise image-based facial landmark detector, which can be applied to single images or video. With supervision-by-registration, we demonstrate (1) improvements in facial landmark detection on both images (300W, ALFW) and video (300VW, Youtube-Celebrities), and (2) significant reduction of jittering in video detections

Extended calculations of energy levels, radiative properties, AJA_{J}, BJB_{J} hyperfine interaction constants, and Land\'e gJg_{J}-factors for nitrogen-like \mbox{Ge XXVI}

Employing two state-of-the-art methods, multiconfiguration Dirac--Hartree--Fock and second-order many-body perturbation theory, highly accurate calculations are performed for the lowest 272 fine-structure levels arising from the $2s^{2} 2p^{3}$, $2s 2p^{4}$, $2p^{5}$, $2s^{2} 2p^{2} 3l$~($l=s,p,d$), $2s 2p^{3}3l$ ($l=s,p,d$), and $2p^{4} 3l$ ($l=s,p,d$) configurations in nitrogen-like Ge XXVI. Complete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Land\'e $g_{J}$-factors, and E1, E2, M1, M2 line strengths, oscillator strengths, and transition rates among these 272 levels are provided. Comparisons are made between the present two data sets, as well as with other available experimental and theoretical values. The present data are accurate enough for identification and deblending of emission lines involving the $n=3$ levels, and are also useful for modeling and diagnosing fusion plasmas

Automatic Engineering of Long Prompts

Large language models (LLMs) have demonstrated remarkable capabilities in solving complex open-domain tasks, guided by comprehensive instructions and demonstrations provided in the form of prompts. However, these prompts can be lengthy, often comprising hundreds of lines and thousands of tokens, and their design often requires considerable human effort. Recent research has explored automatic prompt engineering for short prompts, typically consisting of one or a few sentences. However, the automatic design of long prompts remains a challenging problem due to its immense search space. In this paper, we investigate the performance of greedy algorithms and genetic algorithms for automatic long prompt engineering. We demonstrate that a simple greedy approach with beam search outperforms other methods in terms of search efficiency. Moreover, we introduce two novel techniques that utilize search history to enhance the effectiveness of LLM-based mutation in our search algorithm. Our results show that the proposed automatic long prompt engineering algorithm achieves an average of 9.2% accuracy gain on eight tasks in Big Bench Hard, highlighting the significance of automating prompt designs to fully harness the capabilities of LLMs

Hole Doping Dependence of the Coherence Length in La2−xSrxCuO4La_{2-x}Sr_xCuO_4 Thin Films

By measuring the field and temperature dependence of magnetization on systematically doped $La_{2-x}Sr_xCuO_4$ thin films, the critical current density $j_c(0)$ and the collective pinning energy $U_p(0)$ are determined in single vortex creep regime. Together with the published data of superfluid density, condensation energy and anisotropy, for the first time we derive the doping dependence of the coherence length or vortex core size in wide doping regime directly from the low temperature data. It is found that the coherence length drops in the underdoped region and increases in the overdoped side with the increase of hole concentration. The result in underdoped region clearly deviates from what expected by the pre-formed pairing model if one simply associates the pseudogap with the upper-critical field.Comment: 4 pages, 4 figure