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Graphical abstract Highlights • Boric acid causes the formation of transient network in lactose-modified chitosan. • The active network shows strain-hardening features resembling ECM components. • The super-soft material can reorganize and undergo disassembly. Abstract Developing synthetic materials able to mimic micro- and macrorheological properties of natural networks opens up to novel applications and concepts in materials science. The present contribution describes an active network based on a semi-synthetic polymer, a lactitol-bearing chitosan derivative (Chitlac), and a transient inorganic cross-linker, boric acid. Due to the many and diverse anchoring points for boric acid on the flanking groups of Chitlac, the cross-links constantly break and reform in a highly dynamic fashion. The consequence is a network with unusual non-equilibrium and mechanical properties closely resembling the rheological behavior of natural three-dimensional arrangements and of cytoskeleton. Concepts like network nucleation, reorganization and disassembly are declined in terms of amount of the cross-linker, which acts as a putative motor for remodeling of the network upon application of energy. The out-of-equilibrium and non-linear behavior render the semi-synthetic system of great interest for tissue engineering and for developing in-vitro mimics of natural active matrices. [ABSTRACT FROM AUTHOR]

Abstract: The effects of erosion and accretion of sand dune systems are often underestimated due to the coarse spatial and temporal resolution data set. This paper shows a specific methodology to monitor, at local scale and high repeatability, the crescentic dune of Mónsul in Almería (SE Spain). Precise spatial information based on high resolution profiles has been obtained periodically by repeated GPS surveys. The dune morphology and associated changes due to erosion and accretion are investigated using the GPS methodology in RTK (Real Time Kinematic) mode. This technique introduces significant improvements compared to other techniques for monitoring small areas such as better repeatability, accuracy, reliability, etc. The availability of the Andalusian Positioning Network, an active network over the region, allowed us to monitor the dune throughout GPS profiles capturing its evolution for the period of April–September, 2010. Three GPS campaigns spaced over time were performed. The framework is established by the active network, avoiding the placement of a local control network in this protected area. The main objective of this study is to perform a control methodology based on NRTK (network RTK) positioning supported by a regional active network, with special emphasis on checking and filtering the surveyed data. The numerical and graphical results presented show a balance between the values of erosion and accretion of sand on the dune. [Copyright &y& Elsevier]

Abstract: Precise GNSS-based differential positioning in real time is usually known as the real-time kinematics (RTK) technique. RTK reduces the effects of orbit errors and ionospheric and tropospheric refraction by forming differences between the observables (e.g. double-differences). These effects, however, grow with increasing baseline length, although the use of corrections generated in real-time from an active GNSS network allows these distance-dependent errors to be reduced. This technology increases the reliability of the system and thereby the accuracy of real-time positioning. In this study, the test results of RTK positioning at different test points located in the border area between the Autonomous Communities of the Region of Murcia and the Community of Valencia, in SE Spain, are presented. The analysis is based on three GNSS local active networks present in this border area, namely MERISTEMUM, REGAM and ERVA networks. Test measurements with RTK rover were performed in this region in order to analyze the real-time services offered by these three networks. Moreover, precise coordinates for each test point were determined using Bernese 5.0. The results confirm that it is possible to achieve centimetre-scale accuracy with RTK positioning based on the networks studied, even in border regions. [Copyright &y& Elsevier]

Abstract: In active networks, the Execution Environment in an active node executes user codes to tailor the processing of packets to application needs. However, the existing implementation of a software-based active node has a dilemma of only using the user mode Execution Environment or, alternatively, only using the kernel mode Execution Environment because neither mode of the Execution Environments meets application needs. The dilemma stems from the choice between high overheads of a user mode Execution Environment and poor services of a kernel mode Execution Environment in executing user codes. In this paper, we propose the Dual-Mode Execution Environment to overcome this dilemma, i.e. arguing for the necessity of an Execution Environment that supports dual modes. Currently, we develop and make the Lifetime-Sensitive Quantity-based Policy the workload adjustment policy in the Dual-Mode Execution Environment. We implement the prototype in Windows 2000. We conduct experiments to compare the prototype with active nodes that uses either the user mode Execution Environment or the kernel mode Execution Environment. We prove that the prototype meets application needs and outperforms the compared active nodes. [Copyright &y& Elsevier]

Abstract: Composition of Web services enables collaboration among autonomous business organisations such that they can integrate their services to perform collaborative business activities. It facilitates the development of new services using pre-existing Web services thus reducing development and operational costs. However, the highly distributed, dynamic, and autonomous nature of component Web services gives rise to various issues such as service matchmaking, reliability, availability, security and efficiency. This paper presents a new protocol in order to improve the efficiency of Web services composition. The proposed protocol is based on the peer-to-peer paradigm which exploits the capabilities of underlying networks such that part of the processing is carried out at the network nodes. Efficiency of the proposed protocol is tested through various experiments. Experimental results show that the proposed protocol significantly improves performance by reducing the system response time in the composition of Web services. [Copyright &y& Elsevier]