| 4431. |
- Li, Cheng-Wang, et al.
(författare)
-
Comparison of mechanical properties of various joining processes of aluminum-titanium light alloy
- 2023
-
Ingår i: Suxing Gongcheng Xuebao/Journal of Plasticity Engineering. - : Beijing Res. Inst. of Mechanical and Elec. Technology. - 1007-2012. ; 30:8, s. 138-145
-
Tidskriftsartikel (refereegranskat)abstract
- 5A06 aluminum alloy and TA1 titanium alloy were selected for the connection tests of flow drill screw, ultrasonic clinch and ultrasonic self-piercing riveting. The influence of plate overlap methods on mechanical properties of each group of joints was studied by static tensile tests. The results show that the mechanical properties of the flow drill screw joints and the ultrasonic self-piercing riveted joints are significantly improved when the soft plate is on top during the riveting process. The plate overlap method has little effect on the ultrasonic clinch joint. Flow drill screw joints have the best cushioning and shock absorption performance, but the stability is poor, and it is more limited when applied to body structures. Ultrasonic clinch joints have low cost and simple process, but poor shear resistance and are not suitable for body structures subjected to high stress. Compared with the other two connection methods, the ultrasonic self-piercing riveted connection has the best stability, the best tensile resistance and shear stiffness, and is suitable for much of the structure in lightweight field of automobile body. © 2023 Beijing Res. Inst. of Mechanical and Elec. Technology. All rights reserved.
|
|
| 4432. |
- Li, Jung Shian, et al.
(författare)
-
Scheduling performance enhancement by network coding in wireless mesh networks
- 2012
-
Ingår i: IET Communications. - : Institution of Engineering and Technology. - 1751-8628 .- 1751-8636. ; 6:13, s. 1912-1919
-
Tidskriftsartikel (refereegranskat)abstract
- When a wireless mesh network accommodates interactive applications with quality of service requirements, schedule-based protocols are more suitable than contention-based protocols. In this paper, the problem of determining an appropriate schedule assignment for multiple group transmissions within a spatial time division multiple access link scheduling network is referred to as an integrated multiple-group communication and link scheduling problem. A polynomial-time scheduling algorithm, designated as a source-parallel-aware assignment (SPAA), is proposed to increase the spatial utilisation within each time slot in order to enhance the network throughput. Furthermore, an advanced version of SPAA, designated as joint source-parallel-aware assignment with network coding (JSANC), is proposed to reduce the effects of bottleneck paths on the schedule frame length by flexibly applying conventional or opportunistic network coding approaches. Simulation results show that the proposed algorithms achieve a better network throughput than existing flow-based or particular order-based scheduling schemes.
|
|
| 4433. |
- Li, JIan, et al.
(författare)
-
The friction and wear properties of Polypropylene composite filled with carbon fiber and Polyamide 6
- 2014
-
Ingår i: Journal of Thermoplastic Composite Materials. - : SAGE. - 0892-7057 .- 1530-7980. ; 27:8, s. 1037-1044
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon fiber composites were prepared in order to study the influence of fillers (polyamide 6; PA6) on the tensile and tribological properties of polypropylene (PP) composites. Tensile fracture mechanism was discussed based on the tensile testresults. Tribological tests were conducted on a Mobile Remote Handler-3 (MRH-3) friction and wear tester using a block-on-ring arrangement. It was observed that the carbon fiber (CF) played a main role in the tensile-resistant and wear-resistant properties of the CF/PP composites. The tensile properties were ruled by the fiber–matrix adhesion. Moreover, the excellent tribological performance of the CF/PA6/PP composite is consistent with the worn surface morphology shown.
|
|
| 4434. |
- Li, Rongyang, et al.
(författare)
-
Emotion Arousal Assessment Based on Multimodal Physiological Signals for Game Users
- 2023
-
Ingår i: IEEE Transactions on Affective Computing. - : Institute of Electrical and Electronics Engineers (IEEE). - 1949-3045. ; 14:4, s. 2582-2594
-
Tidskriftsartikel (refereegranskat)abstract
- Emotional arousal, an essential dimension of game users' experience, plays a crucial role in determining whether a game is successful. Game users' emotion arousal assessment (GUEA) is of great importance. However, GUEA often faces challenges, such as selecting emotion-inducing games, labeling emotional arousal, and improving accuracy. In this study, the scheme for verifying the effectiveness of emotion-induced games is proposed so that the selected games can induce the target emotions. In addition, the personalized arousal label generation method is developed to reduce the errors caused by individual differences among subjects. Furthermore, to improve the accuracy of GUEA, the Breath Rate Variability (BRV) signal is used as a GUEA indicator along with commonly used physiological signals. Comparative experiments on GUEA based on multimodal physiological signals are conducted. The experimental result shows that the accuracy of GUEA is improved by adding the BRV signal, up to 92%. IEEE
|
|
| 4435. |
- Li, Shuai, et al.
(författare)
-
Grid-Search Enhanced Tree-Based Machine Learning for Traffic IoT Data Anomaly Detection
- 2022
-
Ingår i: Proceedings of the 12th International Conference on Computer Engineering and Networks. - Singapore : Springer Science+Business Media B.V.. - 9789811969003 ; , s. 3-9
-
Konferensbidrag (refereegranskat)abstract
- Anomaly detection is an important part of machine learning. Detection of outliers in the field of transportation can provide valid data for future traffic predictions or traffic flow analysis. This paper builds a model based on XGBoost to detect outliers in IoT data. The data is preprocessed first, followed by model building. Then we use the grid search to adjust the parameters and substitute the optimal parameters into the building model. To validate the model, we cross-checked it with two benchmark models, iFroset and Random Forest. The final experimental results show that the model constructed in this paper can accurately detect outliers in traffic flow and the accuracy is better than that of the baseline model. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
|
|
| 4436. |
- Li, Wenchen, et al.
(författare)
-
Night Vision Systems in Cars : A Review of Principles, Experimental Results and Recommendations
- 2008
-
Ingår i: Ergonomia: An International Journal of Ergonomics and Human Factors. - 0137-4990. ; 30:2, s. 99-114
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of using a vision enhancement system when driving a car at night, especially those based on infrared image information are reviewed. Principles and a short technical background are given for night vision systems in cars. The following issues are discussed: Human vision at night, infrared image information, and human factors of night vision systems. A proposal is made for using the terms indirect viewing panel and direct viewing panel instead of the terms head up display and head down display. The advantages for older drivers are pointed out. Methodological aspects of how to study human factor aspects of night vision systems are also reviewed. Measures to be used as dependent variables are suggested: Speed, time to collision, eye movements, reaction time, lateral position of the car on the road, and the workload of the driver. Recommendations, based on visual ergonomics, taking into account different visual fields for where to put the image are given. Here suitable image distances, locations, and sizes are discussed.
|
|
| 4437. |
- Liang, Feng, et al.
(författare)
-
LAD-Net : A lightweight welding defect surface non-destructive detection algorithm based on the attention mechanism
- 2024
-
Ingår i: Computers in industry (Print). - : Elsevier. - 0166-3615 .- 1872-6194. ; 161
-
Tidskriftsartikel (refereegranskat)abstract
- Ultrasound welding technology is widely applied in the field of industrial manufacturing. In complex working conditions, various factors such as welding parameters, equipment conditions and operational techniques contribute to the formation of diverse and unpredictable line defects during the welding process. These defects exhibit characteristics such as varied shapes, random positions, and diverse types. Consequently, traditional defect surface detection methods face challenges in achieving efficient and accurate non-destructive testing. To achieve real-time detection of ultrasound welding defects efficiently, we have developed a lightweight network called the Lightweight Attention Detection Network (LAD-Net) based on an attention mechanism. Firstly, this work proposes a Deformable Convolution Feature Extraction Module (DCFE-Module) aimed at addressing the challenge of extracting features from welding defects characterized by variable shapes, random positions, and complex defect types. Additionally, to prevent the loss of critical defect features and enhance the network's capability for feature extraction and integration, this study designs a Lightweight Step Attention Mechanism Module (LSAM-Module) based on the proposed Step Attention Mechanism Convolution (SAM-Conv). Finally, by integrating the Efficient Multi-scale Attention (EMA) module and the Explicit Visual Center (EVC) module into the network, we address the issue of imbalance between global and local information processing, and promote the integration of key defect features. Qualitative and quantitative experimental results conducted on both ultrasound welding defect data and the publicly available NEU-DET dataset demonstrate that the proposed LAD-Net method achieves high performance. On our custom dataset, the F1 score and mAP@0.5 reached 0.954 and 94.2%, respectively. Furthermore, the method exhibits superior detection performance on the public dataset. © 2024 Elsevier B.V.
|
|
| 4438. |
- Liang, Xu, et al.
(författare)
-
A Multi-agent System Based on Activity Theory for Collaborative Network Learning
- 2009
-
Konferensbidrag (refereegranskat)abstract
- Collaborative learning can effectively improve the learning efficiency of learners rather individual learning. Activity theory is a theoretical framework for analyzing human practices as developmental processes with both individual and social levels interlinked at the same time. Learn is a activity, in this paper, we analyze the composition of collaborative network learning activity including goals, subjects, objects, tools and rules. finally, We design a multi-agent system for collaborative network learning, structure and function of every hype agent are discussed
|
|
| 4439. |
- Liang, Xusheng, et al.
(författare)
-
Comparative Study of Layout Analysis of Tabulated Historical Documents
- 2021
-
Ingår i: Big Data Research. - : Elsevier Inc.. - 2214-5796 .- 2214-580X. ; 24
-
Tidskriftsartikel (refereegranskat)abstract
- Nowadays, the field of multimedia retrieval system has earned a lot of attention as it helps retrieve information more efficiently and accelerates daily tasks. Within this context, image processing techniques such as layout analysis and word recognition play an important role in transcribing content in printed or handwritten documents into digital data that can be further processed. This transcription procedure is called document digitization. This work stems from an industrial need, namely, a Swedish company (ArkivDigital AB) has scanned more than 80 million pages of Swedish historical documents from all over the country and there is a high demand to transcribe the contents into digital data. Such process starts by figuring out text location which, seen from another angle, is merely table layout analysis. In this study, the aim is to reveal the most effective solution to extract document layout w.r.t Swedish handwritten historical documents that are featured by their tabular forms. In short, outcome of public tools (i.e., Breuel's OCRopus method), traditional image processing techniques (e.g., Hessian/Gabor filters, Hough transform, Histograms of oriented gradients -HOG- features), machine learning techniques (e.g., support vector machines, transfer learning) are studied and compared. Results show that the existing OCR tool cannot carry layout analysis task on our Swedish historical handwritten documents. Traditional image processing techniques are mildly capable of extracting the general table layout in these documents, but the accuracy is enhanced by introducing machine learning techniques. The best performing approach will be used in our future document mining research to allow for the development of scalable resource-efficient systems for big data analytics. © 2021 Elsevier Inc.
|
|
| 4440. |
- Liang, Xu, et al.
(författare)
-
Enhance Flexibility in Human Agent Interaction a Case Study on IMAS Agent System
- 2008
-
Konferensbidrag (refereegranskat)abstract
- Human Agent Interaction (HAI) is considered as a sub area in Human Computer Interaction (HCI), in which the computer systems are specified as agent systems. Computer agents are different from traditional Information Systems in aspects of autonomy, adaptivity, and persona when interacting with human users. The usability principles in HCI research should be refined to focus on agent special characteristics when designing agent systems. We argue that flexibility should be especially enhanced in such a case.
|
|
