Search

Based on the structure analysis and fault analysis of the hybrid line, this paper proposes an integrated system of protection and fault location which is suitable for the hybrid line. The system is composed of line protection relays on the ends of the hybrid line and section positioning devices on the ends of the cable. It collects three phase currents on both sides of the cable by using flexible optical current transformer which suits to be installed on the joint points. It calculates the differential current at the ends of the cable line through optical fiber and discriminates the fault is whether in or out of the cable line section. Also, it sends the result to the protection devices on both sides of the hybrid line. When the fault is in the cable, the reclosing function on both sides of the line is blocked immediately. In addition, the line protection relays on both sides integrate the traveling wave fault locating function. With receiving section signal, traveling wave fault location can locate the fault point accurately. With lots of simulation tests, it can be proved that the integrated system proposed in this paper can realize the hybrid line protection and precise fault location of the hybrid line. It can greatly improve the power supply reliability of the hybrid lines. At present, the system has been operated in 500 kV cross-linked polyethylene Zhoushan submarine cable hybrid line.

As a concise form of user reviews, tips have unique advantages to explain the search results, assist users' decision making, and further improve user experience in vertical search scenarios. Existing work on tip generation does not take query into consideration, which limits the impact of tips in search scenarios. To address this issue, this paper proposes a query-aware tip generation framework, integrating query information into encoding and subsequent decoding processes. Two specific adaptations of Transformer and Recurrent Neural Network (RNN) are proposed. For Transformer, the query impact is incorporated into the self-attention computation of both the encoder and the decoder. As for RNN, the query-aware encoder adopts a selective network to distill query-relevant information from the review, while the query-aware decoder integrates the query information into the attention computation during decoding. The framework consistently outperforms the competing methods on both public and real-world industrial datasets. Last but not least, online deployment experiments on Dianping demonstrate the advantage of the proposed framework for tip generation as well as its online business values., Accepted By CIKM 2020 Applied Research Track

We developed a deep learning prototype for the purpose of rainfall prediction for the city of Beijing China. It predicts rainfall dynamics in the next two hours with spatial reso-lution of 1km and temporal resolution of 6 minutes. That is a magnitude better than traditional weather forecasting. The computation time is less than 10 seconds, several magnitudes of less computation time than traditional forecasting. This deep learning network combines the strengths of known structures such as U-Net, ResNet, Sqeeze-and-Excitation, and the spatial Attention mod-ule. We rely solely on full convolutional layers instead of RNN layers as used in other weather prediction ef-forts. Meteorologically assessment metrics suggest better performance by the FCN approach. The prototype is now up and running in anticipation for the summer rain season of 2019. This might be the first such service employed by a capital weather service.

Community detection is an important aspect of social network analysis, but social factors such as user intimacy, influence, and user interaction behavior are often overlooked as important factors. Most of the existing methods are single classification algorithms; multi-classification algorithms that can discover overlapping communities are still incomplete. In former works, we calculated intimacy based on the relationship between users, and divided them into their social communities based on intimacy. However, a malicious user can obtain the other user relationships, thus to infer other users interests, and even pretend to be the another user to cheat others. Therefore the information users concerned about needs to be transferred in the manner of privacy protection. In this paper, we propose an efficient privacy preserving algorithm to preserve the privacy of information in social networks. First, during expansion of communities on the base of mining seed, in order to prevent others from malicious users, we verify their identities after they send a request. We make use of the recognition and nontampering of the block chain to store the user's public key and bind to the block address, which is used for authentication. At the same time, in order to prevent the honest but curious users from illegal access to other users' information, we do not send plaintext directly after the authentication, but hash the attributes by mixed hash encryption to make sure that users can only calculate the matching degree rather than know specific information of other users. Analysis shows that our protocol would serve well against different types of attacks.

In this paper, static analysis, modal analysis and harmonic response analysis are carried out on the rotor structure of single-stage double-suction centrifugal pump. The fatigue life of the rotating shaft was analyzed with the nCode Designlife module in ANSYS. The results show that the maximum equivalent stress is greater than the allowable stress of the material and is located at the journal of the transmission torque connected with the coupling. The maximum deformation also occurs here at 0.4857mm. The axis of rotation is liable to resonate at the first natural frequency of the non-rigid body. The frequency which has the greatest influence on the vibration of the rotating shaft is near the third and fourth order natural frequencies of modal analysis and should be avoided. The minimum number of circulation at the maximum stress is 1.785e7 times, and other positions are above 1014 times. The results show that the pump group works stably under the design condition and the rotor performance meets the design requirements.

Takes Macpherson suspension as the research object, the establishment of the two degree of freedom vibration model analysis of frequency response function. Using solid model, analyzed its structural strength under three typical conditions of uneven pavement, braking and steering. Using the quasi-static simulation module in ADAMS/Car, calculated the suspension different conditions stress as the load to analysis the suspension by the finite element method. After the suspension optimization, the stiffness and the vibration performance is consistent on basic, the strength increased by 12.5%, but it is less than the allowable stress of the material. The quality of the Steering Knuckle was reduced by 4%, which ensures the strength and the material saving, the optimization of the suspension mass ratio increases, improved the vehicle comfort.

The current inter-domain routing protocol, namely, the Border Gateway Protocol (BGP), cannot provide end-to-end (E2E) quality-of-service (QoS) guarantees. The main reason is that an autonomous system (AS) can only receive guarantees from its first hop ASes via service level agreements (SLAs). But beyond the first hop, QoS along the path from source to destination AS is not within the source AS's control regime. In this paper, we investigate the feasibility of providing high QoS-guaranteed E2E transit services by utilizing a (small) set of ASes/IXPs to serve as "brokers" to provide supervision, control and resource negotiation. Finding an optimal set of ASes as brokers can be formulated as a Maximum Coverage with B-dominating path Guarantee (MCBG) problem, which we prove to be NP-hard. To address this problem, we design a (1-e-1/4)-approximation algorithm and also an efficient heuristic algorithm when considering additional constraints (e.g., path length). Based on the current Internet topology, we discover a "3540-alliance" subset (accounting only 6.8%) of 52,079 ASes/IXPs, which can provide high QoS guarantees for 99.29% E2E connections.

A new type of clothes-hanger system is designed in this paper in order to solve the problem that exists in all traditional clothes-hanger, that is the inconvenience of maintain. This paper mainly analyzes the working principle and the development of mechanical design and control system design of the clothes-hanger. The clothes-hanger is able to stop automatically while reaching both maximum and minimum places through an overweight and ultra-light detecting mechanism. Meanwhile, the clothes-hanger is able to be controlled by wireless remote controller. The experimental results show that the system is safe and reliable.

With the improvement of radar resolution, the dimension of the high resolution range profile (HRRP) has increased. In order to solve the small sample problem caused by the increase of HRRP dimension, an algorithm based on kernel joint discriminant analysis (KJDA) is proposed. Compared with the traditional feature extraction methods, KJDA possesses stronger discriminative ability in the kernel feature space. K-nearest neighbor (KNN) and kernel support vector machine (KSVM) are applied as feature classifiers to verify the classification effect. Experimental results on the measured aircraft datasets show that KJDA can reduce the dimensionality, and improve target recognition performance.

Micro-piezoelectric disk gyroscope (MPDG) is a miniaturized inertial sensor that uses a pair of degenerate bulk acoustic wave (BAW) modes to detect the angular velocity. To improve the performance of MPDG, there should be an effective method to design this resonant structure. In this paper, the frequencies of drive and sense mode are obtained when the radius of the MPDG varies from 2.2mm to 3.0mm and the thickness of the MPDG varies from 0.8mm to 1.5mm through finite element analysis (FEM). Using a fitting method, the empirical formulae with an excellent fit are induced to predict the influence of the radius and the thickness of the MPDG on the drive and sense mode frequencies. Based on these empirical formulae, the mode-matched equations are introduced. Moreover, the structure parameter of support pin and electrodes are optimized with FEM. These results can be used to design a piezoelectric disk gyroscope.

There are many varieties of materials and suppliers for the PCB assembly process; meanwhile, process modifications as well as order changings happen frequently during production. The PCB assembly industry is suffering uncertainty and unknowingness due to the lack of timely, accurate, and consistent production data. Therefore, real-time production information tracking plays an important role for the PCB assembly industry, which provides the right information to the right person at right time to support the decision making and optimize the production management. This paper applies RFID technology to capture the production data and process production information for PCB assembly enterprises. In a PCB assembly line, machines and materials are equipped with RFID device such as RFID readers and tags to build the real-time data collecting environment. A number of production information processing methods are proposed to extract the production tracking information such as progress, WIP (Work-in-progress) inventory from the mass real-time data through data filtering and selection. Finally, a case study is given to demonstrate the developed methodologies.

Introduced the important influence on the forklift overall performance and job security of the fork structure parameters. Emphasized the pros and cons of the mechanical properties of the forklift fork structure. Analyzed the simplified fork structure and the rated payload then accomplished the static analysis based on ANSYS. Acquired the maximum stress of the fork under the rated payload. Plotted the distribution curve of stress and deformation value along the fork arm. Provided a theoretical reference for the structural design of the forklift fork. Keywords-Fork; ANSYS; FEM

A phase-controlled lower hybrid wave (LHW) multi-junction (MJ) coupler (3(rows)×4(columns)×4 (subwaveguides)) has been developed in the HT-7 tokamak. Simulations show that it is more effective for driving plasma current than an ordinary phase-controlled LHW antenna (3(rows)× 12(columns)) (traditional coupler). The plasma–wave coupling experiments show that the reflection coefficient (RC) is below 10%, implying that the MJ grill can launch the wave into the plasma effectively. The effect of power spectrum launched by the MJ coupler on RC indicates that an optimal condition is requisite for a better coupling in the lower hybrid current drive (LHCD) experiments. Studies indicate that the drive efficiency of the MJ antenna is higher than that of the traditional one, which is mainly ascribed to the discrepancy in impurity concentration, plasma temperature, and spectrum directivity. An improved confinement with an electron internal transport barrier is obtained by LHCD. The analysis shows that the modified negative (low) magnetic shear and the change of radial electric field profile due to LHCD are possible factors responsible for the eITB formation.

Equipped with magnetic field sensor and accelerometer, smartphones offer a novel method for visitors in indoor environments (for example museums). However, this kind of method suffers from accumulated errors over time and high cost of external infrastructures. In this paper, we develop an innovative and low-cost indoor navigation system using various sensors in smartphone. This system consists of an Improved Pedestrian Dead Reckoning (IPDR) part and an error-tolerant magnetic calibration part. Pedestrian position information could be deduced from a magnetic map matching algorithm, combined with IPDR algorithm applying distance estimation and heading estimation. This navigation system requires nothing but a smartphone and it is easy to implement in exhibition scenarios. The preliminary results of experimental measurements in practice present that our algorithm could achieve high accuracy with a promising potential for smartphone-based indoor positioning.

The accuracy of Global Positioning System (GPS) is often combined with the reliability of Inertial Navigation System (INS) to accomplish navigation. This paper proposes an innovative way to filter and fuse the GPS and INS information. UKF is employed to simulate the information convergence of the dynamic model which maintains better performance in nonlinear system. So we can obtain a fair precise filtering result when both are online. At the same time, the INS data is trained with the result as training target when it is the unique input. This paper raises the idea that Support Vector Machine (SVM) is adopted to train the INS data during GPS outage and the simulated annealing is applied to realize the optimization of the parameters of kernel function and the penalty function in the SVM algorithm. Therefore, the integration navigation could retain almost as precise as the GPS when the GPS is off-line.

Compressive sensing (CS) is a sampling technique designed for reducing the complexity of sparse data acquisition. In this paper, a modified Orthogonal Matching Pursuit (OMP) method, called Adaptive Threshold Backtracking OMP (ATBOMP) for compressive sensing and sparse signal reconstruction is presented. Compared with the standard OMP algorithm, the ATBOMP method incorporates an adaptive threshold technique to choose candidate set and ensure the support set's reliability by regularized procession. Through this modification, the ATBOMP method improves the reconstruction probability of the sparse signal and achieves superior performance. Also, the ATBOMP method does not require the sparsity level to be known as a priori. The experiments demonstrate the proposed method's superior performance to that of several other OMP-type and l1 optimization methods. (4 pages)

Distributed compressive sensing (DCS) gives the method for sparse multi-signal ensemble processing. Distributed MIMO radar provides spatial diversity by viewing the targets from different angles to detect stealth targets. In this paper we apply DCS to distributed MIMO radar and propose a joint sparse modeling to get the sparse representation of the received signal ensemble. We develop Joint-OMP algorithm to reconstruct the signal ensemble. Moreover, simulations demonstrate accurate reconstruction from fewer samples than that required by Nyquist theory. And extensive numerical experiments demonstrate that with the same number of samples, processing the signal ensemble simultaneously is more effective and more accurate than processing signals in each receiver with CS separately. (4 pages)

With the quantitative analysis of pollution area mapping rules and business functions of the modular design by means of geographic information systems technology, computer software and other key technologies, this paper preliminary makes the overall framework of the standard drawing of electronic pollution area distribution mapping, and proposes to build the hardware and software operating platform, database structure design standards and form of generation of electronic pollution area mapping.

Fault prognostic technology is one of the core technologies for automatons health management. Basically, the process of the satellite failure is gradual which can be reflected on the trend of the telemetry parameters. This paper proposes the architecture of the navigation satellite fault prognostic system and presents the fault prognostic method based on the trend forecast of the telemetry parameters of the navigation satellite. Moreover, the rules of different types of the telemetry parameters are classified in order to better use in the fault prognostic. On summarize of the prognostic algorithm, ARMA model and improved GM model are built respectively and the advantages and disadvantages of which are analyzed. Experiment result shows that these two models are more effective and useful in trend forecast of the telemetry parameters in satellite fault prognostic, which is of significance for health management and automation.

In order to ensure the safety of engine life limited parts (ELLP) according to airworthiness regulations, a numerical approach integrating one-way fluid structure interaction (FSI) and probabilistic risk assessment (PRA) is developed, by which the variation of flow parameters in a rotor-stator cavity on the safety of gas turbine disks is investigated. The results indicate that the flow parameters affect the probability of fracture of a gas turbine disk since they can change the distribution of stress and temperature of the disk. The failure probability of the disk rises with increasing rotation Reynolds number and Chebyshev number, but descends with increasing inlet Reynolds number. In addition, a sampling based sensitivity analysis with finite difference method is conducted to determine the sensitivities of the safety with respect to the flow parameters. The sensitivity estimates show that the rotation Reynolds number is the dominant variable in safety analysis of a rotor-stator cavity among the flow parameters.

This model proposed an ant colony optimization model to tackle human resource constrained parallel machine scheduling problem with precedence constraints. In this model, four subsystems are designed to solve the problem, including input subsystem which conducts the problem and the ACO model related parameters and output subsystem which exports scheduling and analysis results, sequence searching subsystem which constructs feasible sequence for each ant, human resource scheduling and sequence evaluation subsystem which assigns human resource and determines the duration time of jobs under the allowable amount of operators. The model is demonstrated to be valid using an example case.

This paper introduces a fully integrated low power consumption radio receiver frontend circuit for a Compass (Beidou) and GPS dual mode dual channel system with 2.5 dB NF, 1.02 mm2 areas, and 8 mA of current in 0.18 μm TSMC CMOS process. Except for a few passive components for input matching, other components such as an off-chip low noise amplifier or a balun are not required. With a non-tunable passive image rejection filter, the receiver frontend can achieve around 60 dB gain and 34 dB image rejection.

In this paper the model of trapping force on microsphere near focus in single optical tweezers is built by three dimensional finite-difference time-domain (FDTD) and Maxwell stress tensor methods. Fifth order Gaussian beam based on spherical vector wave function (VSWF) is adopted as simulation light source; the correct light field transmission is obtained. The influences of the wavelength, waist and polarization of light sources, the radius and refractive index of the microsphere on the optical trapping force are discussed. The influence of nearby microsphere and beam polarization on the trapping force of the trapped microsphere in single optical tweezers is analyzed. The effect of beam polarization working on the trapping force of the trapped microsphere is specially analyzed. As results of simulation, the trapping force acting on the microsphere by the circularly polarized beam is larger than that by the linearly polarized beam. The stability of the trapped microsphere in single optical tweezers will be disturbed by the nearby microsphere and lose its balance. Varying the beam polarization will lead to the change of the trapping force of the trapped microsphere.

Two intense magnetic clouds interacted with the same corotating high-speed solar wind stream in two successive rotations in the fall of 1978. In the August 27 event, the cloud was overtaken by the stream, the front half of the cloud still retained the basic properties of a simple intense cloud while the back half was the interaction region with a two-step velocity profile. In the September 25 event, the cloud was overtaking the same stream, its front half was now the interaction region while the back half had a rather more complex structure than a simple, non-interacting cloud. In the second event, the bulk velocity reached a very high peak value more than 900 km/s in the interaction region, and the Alfvenic speed in the cloud body also reached a high value of more than 600 km/s, which was the local solar wind speed. These two events show further the importance of an enhancement of the Al fvenic speed in accelerating the cloud. The properties of the geomagnetic storm and cosmic ray decrease caused by the clouds are also briefly discussed with reference to the Kp category of geomagnetic storms proposed by the author.

Experiments were carried out on 48 unanesthetized, vogotomized, gallamine triethiodide immobilized and artificially ventilated rabbits. Injection of thyrotropin releasing hormone (TRH) into lateral ventricle resulted in a marked increase in respiratory rate and phrenic nerve discharge frequency and a significant elevation of arterial blood pressure. However, no change in respiratory activity and blood pressure was observed when an equal dose of TRH was injected intravenously. On the contrary, morphine administered intravenously produced a decrease in respiratory activity and blood pressure, which could be reversed by TRH applied intralateral-ventricularly. These findings indicate that TRH can stimulate respiratory activity, elevate blood pressure centrally and antagonize morphine-induced depression in respiration and blood pressure.