Entire Generation Process Research Articles

A new generation method of tunnel progressive defect status random field (TPDSRF) for subway tunnel structure

Subway tunnels are exposed to the risk of multiple hazard attacks such as earthquakes, fires, and explosions during operation, which can cause significant damage to their structure. The presence of progressive defects can exacerbate this damage, but existing hazard design methods do not consider their effects, leading to inaccurate damage assessments. To fill this gap, this study proposes a method to characterize the state of progressive defects in the design stage that may appear in a shield tunnel during a tunnel's operational phase. Firstly, based on the progressive defect situation of the operating tunnels, it was determined that the s status of the defects can be described by stochastic and correlation characteristics. To describe these characteristics, the Tunnel Progressive Defect Status Random Field (TPDSRF) is defined. The study then derives the parameters and range of five progressive defects that describe TPDSRF, using a combination of engineering measurement data and literature research. Finally, the study describes the entire generation process in detail and simulates a TPDSRF for a 1000 rings subway tunnel. Results show consistency with preset values and tunnel progressive defect patterns, demonstrating the feasibility of the proposed method. The results of the study can provide a improving initial state of the structure for hazard analysis, which is important and essential for the analysis of structural hazard damage under the consideration of progressive defects.

Phase-matched high-order harmonic generation in pre-ionized noble gases

One of the main difficulties of efficiently generating high-order harmonics in long neutral-gas targets is to reach the phase-matching conditions. The issue is that the medium cannot be sufficiently ionized by the driving laser due to plasma defocusing. We propose a method to improve the phase-matching by pre-ionizing the gas using a weak capillary discharge. We have demonstrated this mechanism, for the first time, in absorption-limited XUV generation by an 800 nm femtosecond laser in argon and krypton. The ability to control phase-mismatch is confirmed by an analytical model and numerical simulations of the entire generation process. Our method allows to increase the efficiency of the harmonic generation significantly, paving the way towards photon-hungry applications of these compact short-wavelength sources.

Tool‘s profiling for rotational volumetric deformation-analytical study

The paper develops in an analytical form an algorithm for the profiling of the active elements of the upper half-die forming which generates by means of plastic rotary volumetric deformation of the frontal teeth. The half die has the revolving axis inclined with respect to the axis of the deformed blank, which rotates around its own axis of symmetry. In the generation process, the generating half die also performs a movement of the blank. The constitutive surfaces of the tooth flanks to be generated are complex surfaces, formed of circular arcs with variable radius and disposed on a conical base surface, on the same axis with the half-die axis. Such teeth are used for front blades in the textile industry or drilling machines which performs, besides the rotational movement of the tool and an alternate rectilinear motion thereof, creating a percussion effect on the work piece. The surfaces of the upper half and the half die teeth may be regarded as reciprocal wrapping surfaces, so that the entire generation process is based on the analytical principles of surface winding. Starting from the constructive shape of the frontal tooth plate, in a classical scheme of the structure of the oscillating motion mechanism of the upper half matrix, the shape of the deformation teeth is determined based on a specific algorithm, based on the general theory of surface winding, and dedicated software products for it.

Simulation and case study on residential stochastic energy use behaviors based on human dynamics

Simulating the stochastic energy use behaviors of occupants plays an important role in the accurate prediction and operational optimization of building energy consumption. There are many types of energy use behaviors in residential buildings with strong randomicity and complex driving forces. A set of reasonable stochastic energy use behaviors simulation method with improved operability and prediction accuracy is required for the stochastic energy use behaviors. Therefore, a description method for residential energy use behaviors is proposed based on the theory of human dynamics. The residential energy use behaviors are divided into persistent behaviors and transient ones according to the method. The characteristics and regularity of these behaviors are described from the inherent decision-making mechanisms, which lays a theoretical foundation for modelling residential stochastic energy use behaviors in residential buildings. Consequently, a simulation model and algorithm for stochastic energy use behaviors are established based on “subject and event mechanism”. The model focuses on the entire generation process from occupants’ movement to energy use behaviors. The occupants’ movement sequences and persistent event sorting units are generated according to the BARABASI priority queue model and the highest priority decision. Also, based on the various control logic, the occurrence of transient behaviors is predicted. Finally, a household is selected for the annual measurement of stochastic energy use behaviors. Based on the above simulation method, MATLAB and NETLOGO are utilized with algorithm programming to realize the dynamic simulation of stochastic energy use behaviors in this household. The accuracy of the model is verified after comparing with the measured data. The research results suggest that the simulation method can accurately predict residential stochastic energy use behaviors and realize the simulation visualization.

The Role of Electron Trajectories in XUV-Initiated High-Harmonic Generation

High-harmonic generation spectroscopy is a powerful tool for ultrafast spectroscopy with intrinsic attosecond time resolution. Its major limitation—the fact that a strong infrared driving pulse is governing the entire generation process—is lifted by extreme ultraviolet (XUV)-initiated high-harmonic generation (HHG). Tunneling ionization is replaced by XUV photoionization, which decouples ionization from recollision. Here we probe the intensity dependence of XUV-initiated HHG and observe strong spectral frequency shifts of the high harmonics. We are able to tune the shift by controlling the instantaneous intensity of the infrared field. We directly access the reciprocal intensity parameter associated with the electron trajectories and identify short and long trajectories. Our findings are supported and analyzed by ab initio calculations and a semiclassical trajectory model. The ability to isolate and control long trajectories in XUV-initiated HHG increases the range of the intrinsic attosecond clock for spectroscopic applications.

A Probabilistic Approach to Error Detection&Correction for Tree-Mapping Grammars

Abstract Rule-based natural language generation denotes the process of converting a semantic input structure into a surface representation by means of a grammar. In the following, we assume that this grammar is handcrafted and not automatically created for instance by a deep neural network. Such a grammar might comprise of a large set of rules. A single error in these rules can already have a large impact on the quality of the generated sentences, potentially causing even a complete failure of the entire generation process. Searching for errors in these rules can be quite tedious and time-consuming due to potentially complex and recursive dependencies. This work proposes a statistical approach to recognizing errors and providing suggestions for correcting certain kinds of errors by cross-checking the grammar with the semantic input structure. The basic assumption is the correctness of the latter, which is usually a valid hypothesis due to the fact that these input structures are often automatically created. Our evaluation reveals that in many cases an automatic error detection and correction is indeed possible.

External Modulation Method for Generating Accurate Linear Optical FMCW

Frequency modulation continuous wave (FMCW) lasers are key components in modern optical imaging. However, current intracavity modulation lasers do not exhibit low-frequency jitter rate and high linearity due to the inherent relaxation oscillations. Although this may be compensated in a direct modulation laser diode using an optoelectronic feedback loop, the available sweep speed is moderately small. In this letter, a special external modulation method is developed to improve the performance of FMCW. Since only the first sideband optical field is used during the entire generation process, phase noise is kept to a minimum and is also independent of the sweep speed. We demonstrate that the linearity and jitter rates do not deteriorate appreciably when the sweep speed is changed over three orders of magnitude, even up to the highest sweep speed of 2.5 GHz/ $\mu \text{s}$ .