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The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom (3-DOF) orienting tasks and regulating stiffness according to variations in interaction forces. However, few soft robotic wrists simultaneously demonstrate dexterous 3-DOF motion and variable stiffness; in addition, they do not fully consider a soft-rigid hybrid structure of integrated muscles and two carpal rows. In this study, we developed a soft-rigid hybrid structure to design a biomimetic soft robotic wrist (BSRW) that is capable of rotating in the x and y directions, twisting around the z-axis, and possessing stiffness-tunable capacity. To actuate the BSRW, a lightweight soft-ring-reinforced bellows-type pneumatic actuator (SRBPA) with large axial, linear deformation (ηlcmax=70.6%, ηlemax=54.3%) and small radial expansion (ηdemax=3.7%) is designed to mimic the motion of skeletal muscles. To represent the function of two-carpal rows, a compact particle-jamming joint (PJJ) that combines particles with a membrane-covered ball-socket mechanism is developed to achieve various 3-DOF motions and high axial load-carrying capacity (>60 N). By varying the jamming pressure, the stiffness of the PJJ can be adjusted. Finally, a centrally positioned PJJ and six independently actuated SRBPAs, which are in an inclined and antagonistic arrangement, are sandwiched between two rigid plates to form a flexible, stable, and compact BSRW. Such a structure enables the BSRW to have a dexterous 3-DOF motion, high load-carrying ability, and stiffness tunability. Experimental analysis verify 3-DOF motion of BSRW, producing force of 29.6 N and 36 N and torque of 2.2 Nm in corresponding rotations. Moreover, the range of rotational angle and stiffness-tuning properties of BSRW are studied by applying jamming pressure to the PJJ. Finally, a system combining a BSRW and a soft enclosing gripper is proposed to demonstrate outstanding manipulation capability in potential applications. [ABSTRACT FROM AUTHOR]

Automatic assembly using manipulators has lately attracted increased attention due to its low cost and high quality. Since a manipulator is entirely rigid, position or angle deviations often cause assembly failure or even cause damage to the manipulator. A series–parallel compliant device that did not produce a significant contact force was developed during this study to achieve reliable assembly when position or angle deviations occurred. The primary objective for this device was for it to be compliant enough to effectively counteract contact forces and move in a specific direction. The device allowed for a relatively significant misalignment during assembly, and it produced a small force, which protected parts and manipulators. It had two compliant components that were connected using a rigid block. Each compliant component consisted of a rigid frame, four elastic limbs with similar "n" shapes, and a square block. Because an elastic material was used, each elastic limb was equivalent to a compliant hinge (or spring), essentially making the device a series–parallel compliant structure. In this way, the device became compliant and could move in a particular direction when the contact force exceeded a specific value. On this basis, the desired compliance of the device was obtained in all directions depending on the compliant deformation, and an optimization method was proposed to determine the parameters of this device based on the kinematic model and a stiffness analysis. Experiments were performed at different working conditions, and their results demonstrate that this device performed reliably during assembly even when a position deviation or an angle deviation occurred. [ABSTRACT FROM AUTHOR]

With the rapid development of Internet of Things (IoT), more and more devices are connected to IoT, leading to an exponential increase in IoT data. However, two problems stand in the way of the further development of IoT. First, IoT data is uploaded directly to the cloud, and the service provider obtains huge profits by analyzing IoT data. However, users can't get benefits, and they have to bear the risk of privacy leakage. Second, centralized storage limits data sharing, which can slow the development of IoT. To solve these problems, this paper proposes an architecture of Blockchain-based Distributed IoT Data Transaction (BDDT). In our proposed BDDT system, users can get benefits by selling their own data, and the service providers buy users' data to gain access. Furthermore, all operations of IoT data transactions are recorded in blockchain. It ensures the traceability and irreversible modification of data transactions. Final, the experimental results prove that the BDDT system has a good performance and excellent safety. [ABSTRACT FROM AUTHOR]

Crowdsourcing application, deemed as a key evolution on the way to vehicular networking, has great potential to provide real-time services. However, existing cloud-based vehicular networking cannot support real-time data transmission with wasting massive bandwidth resources. This paper studies the crowdsourcing application in edge-assistant vehicular networking. To improve the real-time demand of data transmission, we propose the E-node of that owns the learning and semantic analysis abilities. Then we analyze two data transmission scenarios of crowdsourcing for collected data: road map uploading, traffic accident and traffic flow. On the other hand, to address the privacy leakages in the process of data aggregation and data distribution, we separately design time-tolerance anonymous privacy protection algorithm and k − 1 location-offset privacy protection algorithm. Finally, we conduct extensive experiments to verify the effectiveness of our proposed privacy protection algorithms, including time delay, offset probability, privacy leakage probability and accuracy. [ABSTRACT FROM AUTHOR]

With the breakthroughs in sensor technology and internet of things, Vehicular Ad Hoc Network (VANET) is developing into a new generation. The technical challenges of current VANET are decentralized architecture deployment and privacy protection. Since the blockchain owns the characteristics of being decentralized, distributed, collective maintenance and non-tampering, this paper designs a novel decentralized architecture using blockchain technology, which is called blockchain-based VANET. The blockchain-based VANET involves four major stages: blockchain set-up, registration of vehicles, SBMs upload, and blockchain record. It can effectively address the problems of centralization and mutual distrust between entities in current VANET. For protecting identity and location privacy, we propose UGG, IPP and LPP algorithms with the way of dynamic threshold encryption and k-anonymity unity in the stage of SBMs upload of blockchain-based VANET. To quantify the availability of k-anonymity unity, we propose two indicators: connectivity and average distance. Extensive simulations have been conducted to validate the effectiveness of blockchain-based VANET. We analyze the simulation results from four aspects: system time, average distance, connectivity, and privacy leakage. The simulation results show that our proposed architecture performs better in terms of processing time than current architectures. Furthermore, our proposed architecture shows its superior in the aspect of protecting identity and location privacy. [ABSTRACT FROM AUTHOR]

Virtual machine (VM) migration enables flexible and efficient resource management in modern data centers. Although various VM migration algorithms have been proposed to improve the utilization of physical resources in data centers, they generally focus on how to select VMs to be migrated only according to their resource requirements and ignore the relationship between the VMs and servers with respect to their varying resource usage as well as the time at which the VMs should be migrated. This may dramatically degrade the algorithm performance and increase the operating and the capital cost when the resource requirements of the VMs change dynamically over time. In this paper, we propose an integrated VM migration strategy to jointly consider and address these issues. First, we establish a service level agreement-based soft migration mechanism to significantly reduce the number of VM migrations. Then, we develop two algorithms to solve the VM and server selection issues, in which the correlation between the VMs and the servers is used to identify the appropriate VMs to be migrated and the destination servers for them. The experimental results obtained from extensive simulations show the effectiveness of the proposed algorithms compared to traditional schemes in terms of the rate of resource usage, the operating cost and the capital cost. [ABSTRACT FROM AUTHOR]

In graphene, which is an atomic layer of crystalline carbon, two of the distinguishing properties of the material are the charge carriers’ two-dimensional and relativistic character. The first experimental evidence of the two-dimensional nature of graphene came from the observation of a sequence of plateaus in measurements of its transport properties in the presence of an applied magnetic field. These are signatures of the so-called integer quantum Hall effect. However, as a consequence of the relativistic character of the charge carriers, the integer quantum Hall effect observed in graphene is qualitatively different from its semiconductor analogue. As a third distinguishing feature of graphene, it has been conjectured that interactions and correlations should be important in this material, but surprisingly, evidence of collective behaviour in graphene is lacking. In particular, the quintessential collective quantum behaviour in two dimensions, the fractional quantum Hall effect (FQHE), has so far resisted observation in graphene despite intense efforts and theoretical predictions of its existence. Here we report the observation of the FQHE in graphene. Our observations are made possible by using suspended graphene devices probed by two-terminal charge transport measurements. This allows us to isolate the sample from substrate-induced perturbations that usually obscure the effects of interactions in this system and to avoid effects of finite geometry. At low carrier density, we find a field-induced transition to an insulator that competes with the FQHE, allowing its observation only in the highest quality samples. We believe that these results will open the door to the physics of FQHE and other collective behaviour in graphene. [ABSTRACT FROM AUTHOR]

Aim: The present study aimed to explore the protective effect of endogenous sulfur dioxide (SO2) in the development of monocrotaline (MCT)-induced pulmonary hypertension (PH) in rats. Methods: Forty Wistar rats were randomly divided into the MCT group receiving MCT treatment, the MCT+ L-aspartate-β-hydroxamate (HDX) group receiving MCT plus HDX treatment, the MCT+SO2 group receiving MCT plus SO2 donor treatment, and the control group. Mean pulmonary artery pressure (mPAP) and structural changes in pulmonary arteries were evaluated. SO2 content, aspartate aminotransferase activity, and gene expression were measured. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), reduced glutathione (GSH), oxidized glutathione, and malondialdehyde (MDA) levels were assayed. Results: In the MCT-treated rats, mPAP and right ventricle/(left ventricle+septum) increased significantly ( P<0.01), pulmonary vascular structural remodeling developed, and SOD, GSH-Px, CAT, GSH, and MDA levels of lung homogenates significantly increased ( P<0.01) in association with the elevated SO2 content, aspartate aminotransferase activity, and gene expression, compared with the control rats. In the MCT+HDX-treated rats, lung tissues and plasma SO2 content and aspartate aminotransferase activities decreased significantly, whereas the mPAP and pulmonary vascular structural remodeling were markedly aggravated with the decreased SOD, CAT, and GSH levels of lung tissue homogenates compared with the MCT-treated rats ( P<0.01). In contrast, with the use of a SO2 donor, the pulmonary vascular structural remodeling was obviously lessened with elevated lung tissue SOD, GSH-Px, and MDA content, and plasma SOD, GSH-Px, and CAT levels. Conclusion: Endogenous SO2 might play a protective role in the pathogenesis of MCT-induced PH and promote endogenous antioxidative capacities. [ABSTRACT FROM AUTHOR]

Aim: The present study was designed to explore the endogenous production and localization of the sulfur dioxide (SO2)/aspartate aminotransferase pathway in vascular tissues of rats and to examine its vasorelaxant effect on isolated aortic rings, as well as the possible mechanisms. Methods: The content of SO2 in the samples was determined by using high performance liquid chromatography with fluorescence detection. Aspartate aminotransferase activity and its gene expression were measured by an enzymatic method and quantitative RT–PCR, respectively. Aspartate aminotransferase mRNA location in aorta was detected by in situ hybridization. The vasorelaxant effect of SO2 on isolated aortic rings of the rats was investigated in vitro. L-type calcium channel blocker, nicardipine, and L-type calcium channel agonist, Bay K8644, were used to explore the mechanisms by which SO2 relaxed the aortic rings. Results: Aorta had the highest SO2 content among the vascular tissues tested ( P<0.01). The aortic aspartate aminotransferase mRNA located in endothelia and vascular smooth muscle cells beneath the endothelial layer. Furthermore, a physiological dose of the SO2 derivatives (Na2SO3/NaHSO3) relaxed isolated artery rings slightly, whereas higher doses (1–12 mmol/L) relaxed rings in a concentration-dependent manner. Pretreatment with nicardipine eliminated the vasorelaxant response of the norepinephrine-contracted rings to SO2 completely. Incubation with nicardipine or SO2 derivatives successfully prevented vasoconstriction induced by Bay K8644. Conclusion: Endogenous SO2 and its derivatives have a vasorelaxant function, the mechanisms of which might involve the inhibition of the L-type calcium channel. [ABSTRACT FROM AUTHOR]

The spatio-temporal distributions of photo-Dember fields on the semiconductor surface of InAs and the pump wavelength-dependent dynamics of THz radiation from this semiconductor have been investigated with the method of ensemble Monte Carlo Simulation. Our simulations not only confirm the experimental results [P. Gu et al., J. Appl. Phys. 91, 5533(2002)] that the pump wavelength-dependent feature of THz pulse amplitudes for InAs is completely different with that for GaAs, but also point out that the corresponding mechanism is the characteristics of photo-Dember fields. [ABSTRACT FROM AUTHOR]

Recent empirical studies of the real traffic measurement show that the traditional traffic models cannot capture the character of long-range dependence of the traffic. And many computer simulations said that this character has large influences on the network performance. So fractal or self-similar models are more suitable to describe the modern traffic. But there is still little known about the performance of the multiplexer under self-similar traffic. In this paper, a quasi-self-similar traffic model (QSSP) is proposed. Using this model, the upper bond of the cell loss rate and multiplexing gain of the multiplexer are gotten when there are N i.i.d. QSSP inputs. If the sources have different parameters, an efficient numerical algorithm to get this bond is proposed. Simulations indicate that our analysis is correct and accurate. [ABSTRACT FROM AUTHOR]