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Aluminium profiles are widely used in distinct fields since their excellent physical properties, and the quality and efficiency of producing aluminium profiles are largely depending on the extrusion dies. Therefore, the design of the aluminium extrusion die is the most significant part. However, the extrusion die design is a complex process, which includes plenty of data, information, and knowledge. In production, reusing part of the previous design information and knowledge can improve design efficiency. In this case, this study has explored the way to systematically model the design knowledge generated during the aluminium extrusion die design process. Firstly, knowledge representation models have been created, acting as the schema layer of the domain knowledge graph for the aluminium extrusion die design. This knowledge graph is subsequently used as the repository of a Web-based smart design system. By providing the three key functionalities of knowledge representation, semantic retrieval and intelligent recommendation, the smart design system can help engineers effectively reuse previous design knowledge to improve design efficiency and quality.

The introduction of probability model into point set matching has achieved great success. Because the image point set has more outliers and the image has complex transformation, the traditional Gaussian Mixture Model (GMM) does not perform well in image point set matching. In this paper, we propose a Phased Gaussian Mixture Model (PGMM) for point set registration between images. Different from the existing registration algorithms based on GMM, PGMM uses Locality Sensitive Hashing to distinguish the feature reliability of feature points. The initial transformation relation is obtained in the segment with high feature reliability and vector constraint is applied to other segments. The average Hamming distance is used to give different weights to each Gaussian component, which is related to the characteristics between data points and model points. The proposed method has good performance in the case of large image transformation scale.

According to the statistical data of special equipment accidents, and in accordance with the requirements of the "double limit" policy, the height limit device of hoisting machinery includes a variety of types, focusing on the two representative types of fire interrupter device and mechanical drive height limit. By establishing a CAD model of the corresponding device mechanism structure, using the finite element method, simulating the movement of the device mechanism, analyzing the force of the structure, and obtaining relevant information, the cause and mechanism of the device failure can be obtained, and then from the design, manufacture, installation and the use of the device. Reliability improvement and enhancement are carried out in multiple links such as inspection.

The increasing penetration of renewable energy sources reduces the equivalent inertia and spinning reserve. Power systems are becoming more and more vulnerable when subjected to active power deficits. With the trait of quick response and flexible ramp, the energy storage system (ESS) offers a promising capability to counter frequency decline after large disturbances. This paper proposes an event-driven fast frequency response (EFFR) approach for the ESS to sustain frequency stability. A centralized EFFR control framework is established, in which the wide area information is collected, and the disturbance power is broadcasted to ESSs under contingencies. Moreover, a fuzzy logic controller (FLC) is employed to determine the power set-point of the ESS based on the disturbance power and state of charge (SOC). A case study is presented to validate the feasibility and effectiveness of the proposed approach.

In the framework of laser-matter interaction and nonlinear Thomson scattering, we investigate the three-dimensional (3D) motion trajectories and spatial radiation characteristics of the colliding motion electrons with tightly focused circularly polarized Gaussian pulses at different intensities. Combined with the 3D spatial images and the analysis of specific two-dimensional unfolded images, we discover that the amplitude of the motion trajectory increases steadily with increasing laser intensity, the peak radiation power increases rapidly, and the peak radiation azimuth decreases slowly. In addition, by studying the electron motion under the high-intensity ( 10$?> a 0 > 10 ) laser field, we find that the electron motion is retrograde twice when interacting with pulsed laser once. Lastly, by extracting the direction and energy of spatial radiation, we indicate that the existence of a specific laser intensity can make the peak radiation azimuth θ m = 90 ∘ and which intienity provides the maximum conversion rate of laser energy to the peak power of radiation.

We study a two-dimensional quantum walk with only one walker alternatively walking along the horizontal and vertical directions driven by a single two-side coin. We find the analytical expressions of the first two moments of the walker’s position distribution in the long-time limit, which indicates that the variance of the position distribution grows quadratically with walking steps, showing a ballistic spreading typically for quantum walks. Besides, we analyze the correlation by calculating the quantum mutual information and the measurement-induced disturbance respectively as the outcome of the walk in one dimension is correlated to the other with the coin as a bridge. It is shown that the quantum correlation between walker spaces increases gradually with the walking steps.

Additive manufacturing has been widely used in the industry in recent year. Among a range of applications, printing sand structure for casting die or the structure in the construction industry has become more and more popular, since it is cost-effective by using powder printing technology without laser sintering. This paper has explored the additive manufacturing technology used for printing sand structure. To achieve cost-effective and saving materials, methods have been exploring through requirement analysis, materials selection, and design optimization in terms of the mechanical performance of the sand structure. Through 3D modelling, design optimization, and performance improvements, an optimal sand structure for 3D printing is created. This proposed method gives a general way to produce sand structure through 3D printing in the construction and casting industry.

The practical security of a continuous-variable quantum key distribution (CVQKD) system is compromised by various attack strategies. The existing countermeasures against these attacks are to exploit different real-time monitoring modules to prevent different types of attacks, which significantly depend on the accuracy of the estimated excess noise and lack a universal defense method. In this paper, we propose a defense strategy for CVQKD systems to address these disadvantages and resist most of the known attack types. We investigate several features of the pulses that would be affected by different types of attacks, derive a feature vector based on these features as the input of an artificial neural network (ANN) model, and show the training and testing process of the ANN model for attack detection and classification. Simulation results show that the proposed scheme can effectively detect most of the known attacks at the cost of reducing a small part of secret keys and transmission distance. It establishes a universal attack detection model by simply monitoring several features of the pulses without knowing the exact type of attack in advance.

Engineering design is a creative activity which is depending on both scientific knowledge and innovative ideas of human being. Intelligently recommend the scientific knowledge to the designers would certainly shorten the time they spent in finding the data, information and knowledge they need for design decision-making. Thus, they can spend more time in the innovative activity of design. The design of a flexible gear for harmonic drive reducer is a knowledge intense job, where intelligent design method is required to facilitate the design process and thus well applicable. This paper explores a systematic methodology of undertaking intelligent design of such a mechanical component, through on knowledge capture, representation and reuse. A case study on a double-arc flexible gear design is undertaken as the evaluation and improvement of this methodology, whose results have shown the good effectiveness of the methodology in shortening the time for modelling, information retrieval and decision-making.

The key development directions of state grid corporation of China, such as smart grid and centralized data centre, all put forward a lot of demands for cloud computing. In general, it is necessary to build a more flexible, convenient and secure information support platform through cloud computing virtualization, distributed, parallel computing and other technical means. Finally let hardware, software to the direction of centralized service evolution.

The study on the pressure resistance performance of emulsion explosives in deep water can provide theoretical basis for underwater blasting, deep-hole blasting and emulsion explosives development. The sensitizer is an important component of emulsion explosives. By using reusable experimental devices to simulate the charge environment in deep water, the influence of the content of chemical sensitizer on the deep-water pressure resistance performance of emulsion explosives was studied. The experimental results show that with the increasing of the content of chemical sensitizer, the deep-water pressure resistance performance of emulsion explosives gradually improves, and when the pressure is fairly large, the effect is particularly pronounced; in a certain range, with the increase of the content of chemical sensitizer, that emulsion explosives' explosion performance also gradually improve, but when the content reaches a certain value, the explosion properties declined instead; under the same emulsion matrix condition, when the content of NANO2 is 0.2%, that the emulsion explosives has good resistance to water pressure and good explosion properties. The correctness of the results above was testified in model blasting.

The flexible ZnO/SiO2 hybrid nanofiber membrane was prepared via electrospinning followed by high-temperature annealing at 600 °C in the air. The hybrid membrane was researched to prepare a flexible pressure sensor, and the experimental results suggest that the flexible pressure sensor has excellent flexibility under different bending conditions. The sensitivity (I max/I 0) of ZnO/SiO2 hybrid nanofibers is about 12.75 when the blending curvature radius is 1.25 cm−1. Among them, I max means current value when the sample is bending with curvature of 1.25 cm−1 at a voltage of 30 V, and I 0 means current value when the sample is relaxing at a voltage of 30 V. Besides, the prepared nanofibers have excellent pressure sensibilities under various pressures, and the sensitivity (I max/I 0) is up to 20.12 under 32.60 kPa pressure. In addition, the sensor exhibits high sensitivity, reversibility/reproducibility and good performance. The energy-dispersive x-ray spectroscopy shows that atomic percentage of Si to Zn was 43.9%. Additionally, it can be observed from the PL (photoluminescence spectrum) pattern that the sample has fine surface performance. The mechanisms of flexibility and pressure sensitivity are investigated. These results indicate that flexible ZnO/SiO2 hybrid nanofiber films have a bright future in the field of flexible electronic devices.

Quantum walks have significantly different properties compared to classical random walks, which have potential applications in quantum computation and quantum simulation. We study Hadamard quantum walks with coins undergoing different quantum noisy channels and deduce the analytical expressions of the first two moments of position in the long-time limit. Numerical simulations have been done, the results are compared with the analytical results, and they match extremely well. We show that the variance of the position distributions of the walks grows linearly with time when enough steps are taken and the linear coefficient is affected by the strength of the quantum noisy channels.

We demonstrate experimentally the feasibility of continuous variable quantum key distribution (CV-QKD) in dense-wavelength-division multiplexing networks (DWDM), where QKD will typically have to coexist with several co- propagating (forward or backward) C-band classical channels whose launch power is around 0dBm. We have conducted experimental tests of the coexistence of CV-QKD multiplexed with an intense classical channel, for different input powers and different DWDM wavelengths. Over a 25km fiber, a CV-QKD operated over the 1530.12nm channel can tolerate the noise arising from up to 11.5dBm classical channel at 1550.12nm in forward direction (9.7dBm in backward). A positive key rate (0.49kb/s) can be obtained at 75km with classical channel power of respectively -3dBm and -9dBm in forward and backward. Based on these measurements, we have also simulated the excess noise and optimized channel allocation for the integration of CV-QKD in some access networks. We have, for example, shown that CV-QKD could coexist with 5 pairs of channels (with nominal input powers: 2dBm forward and 1dBm backward) over a 25km WDM-PON network. The obtained results demonstrate the outstanding capacity of CV-QKD to coexist with classical signals of realistic intensity in optical networks., Comment: 19 pages, 9 figures. Revised version, to appear in New Journal of Physics

We analyze the process of a discrete-time quantum walk over 4 steps and 5 positions with linear optics elements. The quantum walk is characterized by a ballistic spread of wavepackets along 4 steps. By employing different initial coin states, we observe non-Gaussian distribution of the walkers' finial position, which characterizes a quadratic enhancement of the spread of photon wavepackets compared to a classical random walk. By introducing controllable decoherence, we observe the quantum-to-classical transmission in a quantum walk architecture.

We present a scheme of quantum computing with charge qubits corresponding to one excess electron shared between dangling-bond pairs of surface silicon atoms that couple to a microwave stripline resonator on a chip. By choosing a certain evolution time, we propose the realization of a set of universal single- and two-qubit logical gates. Due to its intrinsic stability and scalability, the silicon dangling-bond charge qubit can be regarded as one of the most promising candidates for quantum computation. Compared to the previous schemes on quantum computing with silicon bulk systems, our scheme shows such advantages as a long coherent time and direct control and readout.

This article aims to provide a review on quantum walks. Starting form a basic idea of discrete-time quantum walks, we will review the impact of disorder and decoherence on the properties of quantum walks. The evolution of the standard quantum walks is deterministic and disorder introduces randomness to the whole system and change interference pattern leading to the localization effect. Whereas, decoherence plays the role of transmitting quantum walks to classical random walks.