The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform

Xuewei Piao - One of the best experts on this subject based on the ideXlab platform.

  • Anchor-Chain: A Seamless Producer Mobility Support Scheme in NDN
    2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017
    Co-Authors: Yizhe Zheng, Xuewei Piao
    Abstract:

    Named Data Networking (NDN) has natural advantages in the consumer mobility support for its design characteristics, while the producer mobility support was left unspecified. Some producer mobility support schemes have been proposed in recent years, which better solved the huge overhead caused by the route aggregation in normal NDN, yet critical issues like long handover latency and high packet loss rate still remain. In this paper, we improved and optimized a quite popular method Anchor-based solution by setting multi-level Anchor nodes strategically based on the network topology hierarchy, which we called Anchor-Chain, and the Interest packet forwarded to the producer would pass through it. After the producer moved, the newly generated Anchor-Chain would reuse the previous forwarding path as far as possible to guide more Interests to the new location of producer and reduce the Interest packets drop rate. Besides, we introduce a mobility preprocess mechanism that takes the advantage of connectionless and multi-path forwarding in NDN to establish the future Interest forwarding path in advance, which assists the producer performs "seamless" handover. By numerical analysis, our approach can reduce the handover latency and improve the response ratio compared with the main current solutions.

  • VTC Spring - Anchor-Chain: A Seamless Producer Mobility Support Scheme in NDN
    2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017
    Co-Authors: Yizhe Zheng, Xuewei Piao
    Abstract:

    Named Data Networking (NDN) has natural advantages in the consumer mobility support for its design characteristics, while the producer mobility support was left unspecified. Some producer mobility support schemes have been proposed in recent years, which better solved the huge overhead caused by the route aggregation in normal NDN, yet critical issues like long handover latency and high packet loss rate still remain. In this paper, we improved and optimized a quite popular method Anchor-based solution by setting multi-level Anchor nodes strategically based on the network topology hierarchy, which we called Anchor-Chain, and the Interest packet forwarded to the producer would pass through it. After the producer moved, the newly generated Anchor-Chain would reuse the previous forwarding path as far as possible to guide more Interests to the new location of producer and reduce the Interest packets drop rate. Besides, we introduce a mobility preprocess mechanism that takes the advantage of connectionless and multi-path forwarding in NDN to establish the future Interest forwarding path in advance, which assists the producer performs "seamless" handover. By numerical analysis, our approach can reduce the handover latency and improve the response ratio compared with the main current solutions.

Yizhe Zheng - One of the best experts on this subject based on the ideXlab platform.

  • Anchor-Chain: A Seamless Producer Mobility Support Scheme in NDN
    2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017
    Co-Authors: Yizhe Zheng, Xuewei Piao
    Abstract:

    Named Data Networking (NDN) has natural advantages in the consumer mobility support for its design characteristics, while the producer mobility support was left unspecified. Some producer mobility support schemes have been proposed in recent years, which better solved the huge overhead caused by the route aggregation in normal NDN, yet critical issues like long handover latency and high packet loss rate still remain. In this paper, we improved and optimized a quite popular method Anchor-based solution by setting multi-level Anchor nodes strategically based on the network topology hierarchy, which we called Anchor-Chain, and the Interest packet forwarded to the producer would pass through it. After the producer moved, the newly generated Anchor-Chain would reuse the previous forwarding path as far as possible to guide more Interests to the new location of producer and reduce the Interest packets drop rate. Besides, we introduce a mobility preprocess mechanism that takes the advantage of connectionless and multi-path forwarding in NDN to establish the future Interest forwarding path in advance, which assists the producer performs "seamless" handover. By numerical analysis, our approach can reduce the handover latency and improve the response ratio compared with the main current solutions.

  • VTC Spring - Anchor-Chain: A Seamless Producer Mobility Support Scheme in NDN
    2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017
    Co-Authors: Yizhe Zheng, Xuewei Piao
    Abstract:

    Named Data Networking (NDN) has natural advantages in the consumer mobility support for its design characteristics, while the producer mobility support was left unspecified. Some producer mobility support schemes have been proposed in recent years, which better solved the huge overhead caused by the route aggregation in normal NDN, yet critical issues like long handover latency and high packet loss rate still remain. In this paper, we improved and optimized a quite popular method Anchor-based solution by setting multi-level Anchor nodes strategically based on the network topology hierarchy, which we called Anchor-Chain, and the Interest packet forwarded to the producer would pass through it. After the producer moved, the newly generated Anchor-Chain would reuse the previous forwarding path as far as possible to guide more Interests to the new location of producer and reduce the Interest packets drop rate. Besides, we introduce a mobility preprocess mechanism that takes the advantage of connectionless and multi-path forwarding in NDN to establish the future Interest forwarding path in advance, which assists the producer performs "seamless" handover. By numerical analysis, our approach can reduce the handover latency and improve the response ratio compared with the main current solutions.

Wei Gu - One of the best experts on this subject based on the ideXlab platform.

  • Robust Tension Control of the Anchor Chain of the Ship Windlass under Sea Wind
    Journal of Computers, 2010
    Co-Authors: Wei Gu
    Abstract:

    Constant tension control of Anchor Chains is important for safety of moored ships. The core driving component of an Anchor windlass system is an induction motor which is a multi-variables, coupled nonlinear system, and is difficult to control. To surmount this problem, a control scheme based on the inverse system method is introduced to linearize an induction motor into a decoupled linear system, and linear controllers are then designed to complete the control task. In addition, theoretical analysis based on the Lyapnov method is carried out to investigate the influence of the time-varying rotor resistance to the control scheme suggested. Both theoretical analysis and numerical simulations show this control scheme is able to keep Anchor Chains at desired tension under sea wind at a time-varying rotor resistance.

  • Constant Tension Control of the Anchor Chain of the Windlass under Sea Wind
    2008 International Workshop on Education Technology and Training & 2008 International Workshop on Geoscience and Remote Sensing, 2008
    Co-Authors: Wei Gu
    Abstract:

    The constant tension control of the Anchor Chain is important for the safety of the moored ships. The key component of the Anchor windlass system is the induction motor which is a multi-variables, coupled nonlinear system, and is difficult to control. To surmount this problem, the inverse system method is introduced to linearize the induction motor into a decoupled linear system, and accordingly linear controllers are designed to complete the control task. The simulation results show this framework is able to keep the Anchor Chain at desired tension under sea wind.

Mark Randolph - One of the best experts on this subject based on the ideXlab platform.

  • Numerical Study of Mobilized Friction along Embedded Catenary Mooring Chains
    Journal of Geotechnical and Geoenvironmental Engineering, 2019
    Co-Authors: Xiaowei Feng, S.r. Neubecker, Mark Randolph, Mark Fraser Bransby, Susan Gourvenec
    Abstract:

    AbstractUnderstanding the soil resistance along an embedded Anchor Chain is imperative for efficient and economic design of an overall mooring system as it determines the magnitude and direction of...

  • Finite Element Simulation of an Embedded Anchor Chain
    Volume 9: Offshore Geotechnics; Honoring Symposium for Professor Bernard Molin on Marine and Offshore Hydrodynamics, 2018
    Co-Authors: Xiaowei Feng, S.r. Neubecker, Susan Gourvenec, Mark Randolph
    Abstract:

    The embedded portion of a mooring line plays an important role for efficient and economic design of an overall mooring system. This paper presents a methodology for numerical simulation of the behaviour of an embedded Anchor Chain as it cuts through the soil, focusing on the tensioning of a catenary mooring. The Coupled Eulerian–Lagrangian (CEL) approach within ABAQUS is used to capture the interaction between the embedded Chain (Lagrangian structure) and the soil (Eulerian material). The Anchor Chain is simulated by a series of rigid cylindrical segments connected together by LINK connectors. Before analysing the global behaviour of an embedded Chain, a calibration exercise is undertaken where a straight multi-link portion of the Chain is displaced normally and axially in soil. The resulting normal and frictional resistances (per unit length) are compared with those adopted in general practice, in order to calibrate the relationship between the diameter of the cylindrical segments and the bar diameter of the Chain. After that, the tensioning process of an Anchor Chain is simulated, starting from an initial configuration with a 9 m length embedded vertically (attached to a fixed padeye), with the remaining length lying on the seabed. Horizontal tensioning of the Chain causes it to cut through the soil until it forms an inverse catenary with an angle of just under 35 degrees to the horizontal at the padeye (and zero degrees at the mudline). The loading curve, and also the inverse catenary profile of the Chain for different angles at the padeye, are shown to agree well with the Neubecker-Randolph closed-form analytical solution. However, the ratio of the tensions at the padeye and the mudline from the CEL results differs significantly from the analytical solution. Insights from the CEL results indicate that this is because the frictional soil resistance is not fully mobilised, particularly for the portion of the Chain in the stronger soil at depth, near the padeye, where the axial displacements are small. This result has significant implications for the geotechnical design of Anchoring systems that involve a (nominally) fixed padeye. The simulation methodology also has considerable potential for exploring the creation of an open trench adjacent to a fixed Anchor due to monotonic and cyclic perturbations of the Anchor Chain.

  • the performance of drag Anchor and Chain systems in cohesive soil
    Marine Georesources & Geotechnology, 1996
    Co-Authors: S.r. Neubecker, Mark Randolph
    Abstract:

    The synthesis of Anchor equilibrium equations with recently derived Chain equilibrium expressions enables calculations for Anchor system capacity which account for the Anchor‐Chain interaction. This forms the basis for a study into the effects of relative Chain size on Anchor performance, and extrapolation of scale‐model tests to prototype events. Applications of these expressions are particularly suited to clay soils, where the failure mechanism of the soil is local and hence the Anchor capacity is essentially independent of Anchor orientation. Expressions are derived for the ultimate holding capacity of Anchors in terms of two fundamental Anchor parameters. Analytical relationships for the development of embedment and capacity with drag distance are shown to compare favorably with numerical solutions and also with field test data.

  • Profile and frictional capacity of embedded Anchor Chains
    Journal of Geotechnical Engineering, 1995
    Co-Authors: S.r. Neubecker, Mark Randolph
    Abstract:

    Previously published methods for solving the force distribution and geometric profile of an embedded Anchor Chain involve numerical solution by an incremental integration technique. By rationalizing the problem, closed-form expressions for both the load development and Chain profile have been derived. These expressions greatly simplify the procedure for estimating the load and inclination of an embedded Chain at some connection point in the soil. The analytical work is corroborated with extensive laboratory test results.

  • PERFORMANCE OF EMBEDDED Anchor ChainS AND CONSEQUENCES FOR Anchor DESIGN
    Offshore Technology Conference, 1995
    Co-Authors: S.r. Neubecker, Mark Randolph
    Abstract:

    With the growth in popularity of floating systems for offshore oil production, there has been an increased focus on the design of permanent mooring systems. It is widely acknowledged that the Anchor Chain plays an important part in the total mooring system by developing frictional load and introducing an inclination of the load at the sub-seabed of Anchorage. By making a simple and valid assumption, the force equilibrium equations of the Chain are simplified to produce closed form expressions for both the force distribution and shows how these equations can be applied to simplify the design of Anchor piles and drag Anchors.

Z Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Anchor Chain molecular system for orientation control in enzyme immobilization
    Bioconjugate Chemistry, 2000
    Co-Authors: Wenhai Shao, Z Zhang, Xianen Zhang, Anthony E G Cass
    Abstract:

    An Anchor-Chain molecular system was constructed for controlled orientation and high activity in enzyme immobilization. A streptavidin recognition peptide (streptag) coding sequence was fused to the 3‘ end of the phoA gene, which codes for E. coli alkaline phosphatase (EAP). Both the wild-type (WT) and the Asp-101 → Ser (D1O1S) mutant were modified with the streptag sequence with or without the insertion of a flexible linker peptide [-(Gly-Ser)5-] coding sequence. The fused genes were cloned into the vector pASK75 and expressed in the periplasm of the host cell Escherichia coli SM547. The proteins were released by osmotic shock and purified by ion-exchange chromatography. Enzyme activities of all proteins were measured spectrophotometrically with ρ-nitrophenyl phosphate as the substrate. Specific activities of D101S-streptag and D101S-linker-streptag enzymes were increased 25- or 34-fold over the WT, respectively. These fusion proteins were then immobilized on microtiter plates through streptag−streptavid...

  • STRESS ANALYSIS OF STUD Anchor Chain
    1991
    Co-Authors: Z Wu, Yigang He, Z Zhang
    Abstract:

    This paper discusses the stress distributions of a stud Anchor Chain subjected to tensile force. With the stud Anchor Chain phi 28A2 as an example, the planar holographic photoelastic stress tests and finite element calculation, the slice tests of three dimensional photoelastic stress and the theoretical calculation of curved beam were carried out. Simple formulae for calculating limit stress are given and the precision is satisfactory.