To address the problems of low accuracy, difficult deployment and high calibration cost of visual manipulator in complex system environments, a robust joint modelling and optimization method for visual manipulators was proposed. Firstly, the subsystem models of the visual manipulator were integrated together, and the sample data such as servo motor rotation angles and manipulator end-effector coordinates were collected randomly in the workspace of the manipulator. Then, an Adaptive Multiple-Elites-guided Composite Differential Evolution algorithm with shift mechanism and Layered Optimization mechanism (AMECoDEs-LO) was proposed. Simultaneous optimization of the joint system parameters was completed by using the method of parameter identification. Principal Component Analysis (PCA) was performed by AMECoDEs-LO on stage data in the population, and with the idea of parameter dimensionality reduction, an implicit guidance for convergence accuracy and speed was realized. Experimental results show that under the cooperation of AMECoDEs-LO and the joint system model, the visual manipulator does not require additional instruments during calibration, achieving fast deployment and a 60% improvement in average accuracy compared to the conventional method. In the cases of broken manipulator linkages, reduced servo motor accuracy and increased camera positioning noise, the system still maintains high accuracy, which verifies the robustness of the proposed method.
Due to complex structure of Three-Dimensional Stacked Integrated Circuit (3D SIC), it is more difficult to design an efficient test structure for it to reduce test cost than for Two-Dimensional Integrated Circuit (2D IC). For decreasing cost of 3D SIC testing, a Three-Dimensional Linear Feedback Shift Register (3D-LFSR) test structure was proposed based on Linear Feedback Shift Register (LFSR), which can effectively adapt to different test phases of 3D SIC. The structure was able to perform tests independently in the pre-stacking tests. After the stacking, the pre-stacking test structure was reused and reconfigured into a test structure suitable for the current circuit to be tested, and the reconfigured test structure was able to further reduce test cost. Based on this structure, the corresponding test data processing method and test flow were designed, and the mixed test mode was adopted to reduce the test time. Experimental results show that compared with the dual-LFSR structure, 3D-LFSR structure has the average power consumption reduced by 40.19%, the average area overhead decreased by 21.31%, and the test data compression rate increased by 5.22 percentage points. And, using the hybrid test mode reduces the average test time by 20.49% compared to using the serial test mode.
Focusing on the characteristics of small objects in images, such as less feature information, low percentage, and easy to be influenced by the environment, a small object detection algorithm based on split mixed attention was proposed, namely SMAM-YOLO. Firstly, by combining Channel Attention (CA) and Spatial Attention (SA), as well as recombining the connection structures, a Mixed Attention Module (MAM) was proposed to enhance the model’s representation of small object features in spatial dimension. Secondly, according to the different influence of receptive fields with different sizes on the object, a Split Mixed Attention Module (SMAM) was proposed to adaptively adjust the size of the receptive field according to the scale of the input feature map, and the mixed attention was used to enhance the ability to capture small object feature information in different branches. Finally, the core residual module in YOLOv5 was improved by using SMAM, and a feature extraction module CSMAM was proposed on the basis of CSPNet (Cross Stage Partial Network) and SMAM, and the additional computational overhead of CSMAM can be ignored. Experimental results on TinyPerson dataset show that compared with the baseline algorithm YOLOv5s, when the Intersection over Union (IoU) threshold is 0.5, the mean Average Precision (mAP50) of SMAM-YOLO algorithm is improved by 4.15 percentage points, and the detection speed reaches 74 frame/s. In addition, compared with some existing mainstream small object detection models, SMAM-YOLO algorithm improves the mAP50 by 1.46 - 6.84 percentage points on average, and it can meet the requirements of real-time detection.
Short text classification is an important research problem of Natural Language Processing (NLP), and is widely used in news classification, sentiment analysis, comment analysis and other fields. Aiming at the problem of data sparsity in short text classification, by introducing node and edge weight features of corpora, based on Graph ATtention network (GAT), a new graph attention network named Node-Edge GAT (NE-GAT) by fusing node and edge weight features was proposed. Firstly, a heterogeneous graph was constructed for each corpus, Gravity Model (GM) was used to evaluate the importance of word nodes, and edge weights were obtained through Point Mutual Information (PMI) between nodes. Secondly, a text-level graph was constructed for each sentence, node importance and edge weights were integrated into the update process of nodes. Experimental results show that, the average accuracy of the proposed model on the test sets reaches 75.48%, which is better than those of the models such as Text Graph Convolution Network (Text-GCN), Text-Level-Graph Neural Network (TL-GNN) and Text classification method for INductive word representations via Graph neural networks (Text-ING). Compared with original GAT, the proposed model has the average accuracy improved by 2.32 percentage points, which verifies the effectiveness of the proposed model.
By removing irrelevant features from the original dataset and selecting good feature subsets, feature selection can avoid the curse of dimensionality and improve the performance of learning algorithm.In the process of feature selection, only the dynamically change information between the selected features and classes is considered, and interaction relevance between the candidate features and the selected features is ignored by Dynamic Change of Selected Feature with the class (DCSF) algorithm. To solve this problem, a Dynamic Relevance based Feature Selection (DRFS) algorithm was proposed. In the proposed algorithm, conditional mutual information was used to measure the conditional relevance between the selected features and classes, and interaction information was used to measure the synergy brought by the candidate features and the selected features, so as to select relevant features and remove redundant features then obtain good feature subsets. Simulation results show that, compared with existing algorithms, the proposed algorithm can effectively improve classification accuracy of feature selection.
To solve the problem that the antenna resources in heterogeneous network are limited which leads to the unrealizable Interference Alignment (IA), a partial IA scheme for maximizing the utilization of antenna resources was proposed based on the characteristics of heterogeneous network. Firstly, a system model based on partial connectivity in heterogeneous network was built and the feasibility conditions for entire system to achieve IA were analyzed. Then, based on the heterogeneity of network (the difference between transmitted power and user stability), the users were assigned to different priorities and were distributed with different antenna resources according to their different priorities. Finally, with the goal of maximizing total rate of system and the utilization of antenna resources, a partial IA scheme was proposed, in which the high-priority users had full alignment and low-priority users had the maximum interference removed. In the Matlab simulation experiment where antenna resources are limited, the proposed scheme can increase total system rate by 10% compared with traditional IA algorithm, and the received rate of the high-priority users is 40% higher than that of the low-priority users. The experimental results show that the proposed algorithm can make full use of the limited antenna resources and achieve the maximum total system rate while satisfying the different requirements of users.
BWDSP100 is a 32-bit static scalar Digital Signal Processor (DSP) with Very Long Instruction Word (VLIW) and Single Instruction Multiple Data (SIMD) features, which is designed for high-performance computing. Its Instruction Level Parallelism (ILP) is acquired though clustering and special SIMD instructions. However, the existing compiler framework can not provide support for these SIMD instructions. Since BWDSP100 has much SIMD vectorization resources and there are very high requirements in radar digital signal processing for the program performance, an SIMD optimization which surpported the selection of single or double word mode was put forward based on the traditional Open64 compiler according to the characteristics of BWDSP100 structure, and it can significantly improve the performance of some compute-intensive programs which are widely used in DSP field. The experimental results show that this algorithm can achieve speedup of 5.66 on average compared with before optimization.
Conventional approaches for Common Weights (CW) generation in Data Envelopment Analysis (DEA) are either non-linear or scale-relevant. To solve this problem, according to the demand of military training performance evaluation, a new method was proposed to generate CW in DEA. The new method took DEA efficient units as the basis of calculation. Firstly, training data were normalized, and then multi-objective programing was employed for CW generation, which can lead to a fairer and more reasonable ranking of performances. The proposed method is not only linear, but also scale-irrelevant. Lastly, a military application illustrates that the proposed method is scientific and effective.
As the instantaneous Channel State Information (CSI) of source to relay and relay to destination affects the overall Bit Error Rate (BER) of the cooperative communication system, a relay selection scheme which evaluated the two-stage channel coefficients was proposed. Firstly, the channel coefficients of source-relay channel and the channel coefficients of relay-destination channel were compared according to the CSI of each candidate relay, and the worse one was found out. Moreover, a node set containing the approximate optimal relays was obtained by sorting the candidate relays based on their worse channel coefficients. Finally, the relay with the highest summation of the two-stage channel coefficients in the set was selected as the one which participated in the cooperative transmission. The simulation results reveal that the Signal-to-Noise Ratio (SNR) of the proposed relay selection scheme respectively decreases by 0.4 dB and 0.2 dB compared with the best worse channel selection scheme and the delay selection scheme based on the nearest neighbor relation, when the number of candidate relay nodes is 100 and 5, and the BER decreases to 10-4 and 10-5. In general, the proposed scheme can expend the information transmission range and improve the reliability in the wireless relay network.
In order to improve the transformation efficiency of tile-pyramid image, a 15-parameter projection transformation method was established by quartic polynomial based on the view model of digital earth. The influencing factors for selecting the size of tile image were discussed theoretically, and an optimization method to determine the size and depth of tile-pyramid was given. To test this algorithm, a basic digital earth environment BDE2 was constructed by adopting JOGL. The analysis and experimental results show that tile-pyramid in 10m pixel accuracy constructed by this algorithm only has 10 layers and less than 5×10-5 average error; meanwhile, the proposed algrithm has low complexity, close stitching, high definition and low distortion, and can effectively avoid stitch cracks and characteristics distortion after the image is transformed.
In the non-overlapping filed of multi-camera system, the single-shot person identification methods cannot well deal with appearance and viewpoint changes. Based on the multiple frames acquired from surveillance cameras, a new technique which combined Hidden Markov Model (HMM) with appearance-based feature was proposed. First, considering the structural constraint of human body, the whole-body appearance of each individual was equally vertically divided into sub-images. Then multi-level threshold method was used to extract Segment Representative Color (SRC) and Segment Standard Variation (SSV) feature. The feature dataset acquired from multiple frames was applied to train continuous density HMM,and the final recognition was realized by these well-trained model. Extensive experiments on two public datasets show that the proposed method achieves high recognition rate, improves robustness against viewpoint changes and low resolution, and it is simple and easy to realize.
In order to enrich and improve the ability of the existing models for reasoning and predicting with 3D cardinal direction relations and enhance the usability of the existing models, and then better meet the demands of real applications for complex 3D spatial data, the inverse reasoning of 3D cardinal direction relations was studied. After deeply studying the theory of n-dimensional block algebra, an algorithm for computing the inverse of the basic 3D cardinal direction relations on the basis of 3D block algebra was devised. Theoretical analysis and the results of the example show that the proposed algorithm is correct and complete. This work can better enhance the power of intelligent analysis and processing for the complex 3D direction relations of the spatial database.
Concerning the problem that it is difficult for the users in cloud computing to obtain the high-quality and personalized cloud services provided by a large number of cloud providers, a trust model based on user types and privacy protection for the personalized cloud services was proposed. Firstly, the users were divided into familiar users, strange users and normal users according to the transaction history. Secondly, a fair and reasonable trust evaluation Agent was introduced to protect users' privacy, which could evaluate the trust relationship between requesters and providers based on the user types. Lastly, in view of the dynamics of trust, a new updating mechanism combined with the transaction time and transaction amount was provided based on Quality of Service (QoS). The simulation results show that the proposed model has higher transaction success rate than AARep and PeerTrust. The transaction success rate can be increased by 10% and 16% in the harsh environment where the malicious user ratio reaches 70%. This method can improve transaction success rate, and has a strong ability to withstand harsh environments.