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This study proposes a remaining useful life (RUL) prediction method using limited degradation data with an unknown degradation model for hydraulic pumps with long service lives and no failure data in turbine control systems. The volumetric efficiency is calculated based on real-time monitoring signal data, and it is used as the degradation indicator. The optimal degradation curve is established using the degradation trajectory model, and the optimal probability distribution model is selected via the K-S test. The above process was repeated to optimize the degradation model and update parameters in different performance degradation stages of the hydraulic pump, providing quantification of the prediction uncertainty and enabling accurate online prediction of the hydraulic pump’s RUL. Finally, an RUL test bench for hydraulic pumps is built for verification. The results show that the proposed method is convenient, efficient, and has low model complexity. The method enables online accurate prediction of the RUL of hydraulic pumps using only limited degradation data, with a prediction accuracy of over 85%, which meets practical application requirements.

Ti-CFRP-Ti laminated stacks have been widely used in aviation, aerospace, shipbuilding and other industries, owing to its excellent physical and electrochemical properties. However, chip blockages occur easily when drilling into Ti-CFRP-Ti laminated stacks, resulting in a rapid rise of drilling temperature and an increase of axial drilling force, which may lead to the intensification of tool wear and a decline of drilling quality. Cutting force signals can effectively reflect the drilling process and tool condition, however, the traditional plate dynamometer is typically difficult in realizing the follow-up online measurement. Therefore, an intelligent tool holder system for real-time sensing of the cutting force is developed and constructed in this paper, and the variable parameter drilling method of Ti-CFRP-Ti laminated stacks is studied on this basis. Firstly, an intelligent tool holder system with high flexibility and adaptability is designed; Secondly, a cutting force signal processing method based on compressed sensing (CS) theory is proposed to solve the problem of high-frequency signal transmission; Lastly, the drilling experiment of Ti-CFRP-Ti laminated stacks is carried out based on the intelligent tool holder system, and the drilling parameters are optimized using a compromise programming approach and analytic hierarchy process (AHP). The comparison of results show that the optimized drilling parameters can effectively reduce the hole wall surface roughness and improve the drilling efficiency while ensuring a small axial force.

We used the virtual hand illusion paradigm to investigate the effect of physical load on perceived agency and body ownership. Participants pulled a resistance band that required exerting a force of 1 N, 10 N, or 20 N while operating a virtual hand that moved in synchronous or out of sync with their own hand. Explicit agency and ownership ratings were obtained, in addition to intentional binding and skin conductance as implicit measures of agency and ownership. Physical load increased perceived subjective load but showed no main effect, while synchrony effects were found on all agency and ownership measures. Interestingly, load did interact with synchrony in implicit agency and explicit ownership, by reducing and eliminating synchrony effects as movement synchrony was reduced with higher physical load. Furthermore, consistent with previous claims, implicit agency increased with perceived effort associated with higher physical load.

Public key cryptographic primitive (e.g., the famous Diffie-Hellman key agreement, or public key encryption) has recently been used as a standard building block in authenticated key agreement (AKA) constructions for wireless sensor networks (WSNs) to provide perfect forward secrecy (PFS), where the expensive cryptographic operation (i.e., exponentiation calculation) is involved. However, realizing such complex computation on resource-constrained wireless sensors is inefficient and even impossible on some devices. In this work, we introduce a new AKA scheme with PFS for WSNs without using any public key cryptographic primitive. To achieve PFS, we rely on a new dynamic one-time authentication credential that is regularly updated in each session. In particular, each value of the authentication credential is wisely associated with at most one session key that enables us to fulfill the security goal of PFS. Furthermore, the proposed scheme enables the principals to identify whether they have been impersonated previously. We highlight that our scheme can be very efficiently implemented on sensors since only hash function and XOR operation are required.

Named Data Network (NDN) technology can efficiently mitigate the negative influence due to instable links and dynamic topology on MANET performance. Considering MANET nodes’ mobility, this paper enhances NDN’s shortest path routing algorithm by storing the interest packets generated by the consumers in the pending interest tables (PITs) of the shortest path’s neighboring nodes, aiming at building the backup paths for transmitting back the requested data packets, so as to mitigate the shortest path disruption problem caused by MANET topology dynamicity. This paper designs and implements a simulation platform based on NS3/ndnSIM, and the experimental results indicate that, the enhanced shortest path plus backup (SPPB) algorithm can effectively decrease the average request response delay and improve successful request response ratio.

Network emulation is a vital testing and verification approach for networking protocols of all layers, as well as for application software during a network’s entire life-cycle from designing to maintenance phases. Network emulation method combines the merits of simulation and test-bed, and balances cost and accuracy. This paper introduces a promising cloud-based network emulati on platform, which leverages a set of novel virtualization and cloud related technologies to implement flexibility, agility and scalability in network emulation domain. Aiming at realizing high fidelity (HiFi) network emulation, External physical network nodes should be able to connect and communicate with the emulated nodes. This paper elaborates an innovative strategy to integrate outside physical nodes with virtual nodes inside of the emulation platform to implement virtual and physical nodes fused network emulation. Functional tests are carried out and indicate that the proposed strategy can effectively bridge the physical node to the virtual platform to achieve HiFi network emulation. Besides, performance evaluation also illustrates that the derived strategy can efficiently utilize the limited computation and networking resources of the platform so to achieve sufficient scalability and flexibility for the typical emulation scenarios.

Information Centric Networking (ICN) is a promising future networking architecture, and Named Data Networking (NDN) is considered to be its authoritative and representative scheme. In recent years, applying ICN/NDN concept in Mobile Ad-hoc Network (MANET), i.e. Name Data Mobile Ad-hoc Network (NDMANET), becomes a research hotspot. Compared with traditional IP protocol, NDN scheme is thought to be more robust and profitable to the node mobility and dynamically changed topologies in MANET. This paper focuses on NDMANET’s in-networking caching strategy, which provides a great flexibility and efficiency for data dissemination and is a vital feature of NDMANET. Firstly, the paper investigates and analyzes some existing caching strategies which are widely applied in the ICN/NDN domain. On that basis, a novel Content Popularity and Distance based Interval (CPDI) caching strategy is derived for NDMANET, with the purpose of improving its network performance. Comprehensive simulation experiments have been carried out and the results illustrate that the proposed CPDI caching strategy can introduce considerable improvements on the average cache hit ratio, the average number of cached data packets, and the average energy consumption with only slightly degrading the average download delay.

Information Centric Network (ICN) is a promising future networking architecture, while Named Data Networking (NDN) is regarded as ICN’s representative and authoritative scheme. In the recent past, applying ICN/NDN concept in mobile ad-hoc network (MANET), i.e. Named Data Mobile Ad-hoc Network (NDMANET), has attracted a plenty of research efforts. Compared to legacy IP protocol, NDN scheme is considered to be more robust and profitable to the node mobility and the dynamically changed topologies in the MANET domain. This paper focuses on NDMANET’s packet forwarding protocols, which to a large extent decides the efficiency of data dissemination and is a vital module of NDMANET. Firstly, the paper investigates and analyzes some existing packet forwarding protocols, which are widely accepted in NDMANET. On that basis, an innovative distance-aware data forwarding (DDF) protocol is elaborated for NDMANET, with the purpose of further enhancing its network performance. Comprehensive simulation experiments have been conducted and the results illustrate that the proposed DDF protocol can introduce considerable reduction in bandwidth and in energy consumption, with only slightly degrading the response ratio.

In this study, a novel aluminum phosphate (AlPO4) heat-resistant layer reinforced with aluminum silicate fiber (ASF) was successfully compounded on a poly(ether sulfone) (PES) matrix via the preparation process of high-temperature heat treatment and vacuum hot-pressing sintering technique. The influence of the ASF content on the morphology, thermal, mechanical, and dielectric properties of the as-fabricated aluminum silicate fiber reinforced aluminum phosphate–poly(ether sulfone) (ASF/AlPO4–PES) layered composite was investigated. The results reveal that the incorporation of aluminum silicate fiber/aluminum phosphate (ASF/AlPO4) heat-resistant layer can significantly improve the thermal stability and mechanical performances of the PES matrix composites. Compared with the pristine PES, the ASF/AlPO4–PES layered composite containing 8.0 wt % ASF exhibited better high-temperature resistance properties (300 °C) and a lower thermal conductivity (0.16 W m−1 K−1). Furthermore, the dielectric constant and dielectric loss tangent of this PES matrix composite decreased to 2.16 and 0.007, respectively. Meanwhile, the frequency stability of the dielectric properties for the ASF/AlPO4–PES layered composites was remarkably enhanced with increasing ASF addition at frequencies ranging from 102 Hz to 5 MHz. This was attributed to the existence of microscopic pores within the ASF/AlPO4 layer and the strong interfacial bonding between the ASF/AlPO4 layer and the PES matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45542.