| 1. |
- Chen, Hong, et al.
(författare)
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A statistical MAC protocol for heterogeneous-traffic human body communication
- 2013
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Konferensbidrag (refereegranskat)abstract
- In wireless body sensor networks (WBSN) and wireless body area networks (WBAN), sensor nodes have different bandwidth requirements, therefore, heterogeneous traffic is created. In this paper, we propose a statistical medium access control (MAC) protocol with periodic synchronization for use in heterogeneous traffic networks based on human body communication (HBC). The MAC protocol is designated to ensure energy efficiency by means of flexible time slot allocation and a statistical frame. The statistical frame is intended to increase the sleep time and keep low duty cycles in each beacon period. The MAC protocol was fully implemented on our HBC platform. The experimental results proved that the proposed MAC protocol is compact and energy-efficient.
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| 2. |
- Chen, S.H., et al.
(författare)
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A crack perpendicular to a bimaterial interface an interface in finite solid
- 2003
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Ingår i: International Journal of Solids and Structures. - : Elsevier, UK. - 0020-7683. ; 40:11, s. 2731-55
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Tidskriftsartikel (refereegranskat)abstract
- The dislocation simulation method is used in this paper to derive the basic equations for a crack perpendicular to the bimaterial interface in a finite solid. The complete solutions to the problem, including the T stress and the stress intensity factors are obtained. The stress field characteristics are investigated in detail. It is found that when the crack is within a weaker material, the stress intensity factor is smaller than that in a homogeneous material and it decreases when the distance between the crack tip and interface decreases. When the crack is within a stiffer material, the stress intensity factor is larger than that in a homogeneous material and it increases when the distance between the crack tip and interface decreases. In both cases, the stress intensity factor will increase when the ratio of the size of a sample to the crack length decreases. A comparison of stress intensity factors between a finite problem and an infinite problem has been given also. The stress distribution ahead of the crack tip, which is near the interface, is shown in details and the T stress effect is considered.
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| 3. |
- Chen, S.H., et al.
(författare)
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Finite boundary effects in problem of a crack perpendicular to and terminating at a bimaterial interface
- 2005
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Ingår i: Acta Mechanica Sinica. - Heidelberg : Springer Berlin. - 0567-7718. ; 21:1, s. 56-64
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Tidskriftsartikel (refereegranskat)abstract
- The problem of a crack perpendicular to and terminating at an interface in bimaterial structure with finite boundaries is investigated. The dislocation simulation method and boundary collocation approach are used to derive and solve the basic equations.Two kinds of loading form are considered when the crack lies in a softer or a stiffer material, one is an ideal loading and the other one fits to the practical experiment loading. Complete solutions of the stress field including the T stress are obtained as well as the stress intensity factors. Influences of T stress on the stress field ahead of the crack tip are studied. Finite boundary effects on the stress intensity factors are emphasized. Comparisons with the probled presented by Chen et al. (int. J. Solids and Structure, 2003,40, 2731-2755) are discussed also.
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| 4. |
- Chen, Yuanfang, et al.
(författare)
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The scheme of mitigating the asymmetric links problem in wireless sensor networks
- 2010
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the radio irregularity (RI) phenomenon and its impact on communication performance in wireless sensor networks (WSNs). Based on the theoretical analysis, we find that the RI phenomenon induces the asymmetric links problem. According to this discovery, we propose a novel HCT (Hop-count Correction Tree) scheme to handle this problem. HCT utilizes graph theoretical method to get a search tree and correct the hop count error that appears in the adjacent nodes. Practical results obtained from testbed experiments demonstrate that this solution can greatly improve localization accuracy in the presence of RI
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| 5. |
- Li, Cheng-Wang, et al.
(författare)
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Comparison of mechanical properties of various joining processes of aluminum-titanium light alloy
- 2023
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Ingår i: Suxing Gongcheng Xuebao/Journal of Plasticity Engineering. - : Beijing Res. Inst. of Mechanical and Elec. Technology. - 1007-2012. ; 30:8, s. 138-145
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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.
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