Global decentralised stabilisation for a class of uncertain large-scale feedforward nonlinear systems

In this paper, the problem of global decentralised stabilisation for a class of uncertain large-scale feedforward nonlinear systems is investigated. The system under consideration is allowed to contain unknown non-Lipschitz continuous nonlinear terms. The design of the global decentralised controllers takes a two steps procedure. First of all, based on the adding a power integrator technique and the homogeneous domination approach a local homogeneous decentralised controller is proposed for each subsystem of the large-scale feedforward nonlinear system. Then, we integrate a series of nested saturation functions with the homogeneous decentralised controllers and adjust the saturation levels to ensure globally asymptotic stability of the closed-loop system. Simulation studies are conducted to illustrate the effectiveness of the proposed control method.     

Segment-based proxy caching for Internet streaming media delivery

The proliferation of multimedia content on the Internet poses challenges to existing content delivery networks. While proxy caching can successfully deliver traditional text-based static objects, it faces difficulty delivering streaming media objects because of the objects' sizes as well as clients' rigorous continuous delivery demands. We present two techniques supporting segment based proxy caching of streaming media. We evaluated these techniques in simulations and real systems.     

Clinical efficacy of amniotic membrane transplantation in the treatment of various ocular surface diseases.

PURPOSE: To investigate the efficacy of permanent amniotic membrane transplantation (AMT) for the treatment of various ocular surface diseases. METHODS: The medical records of 62 eyes from 58 patients who had undergone permanent AMT were reviewed. The amniotic patches were grafted for the treatment of neurotrophic ulcers (n=15), inflammatory corneal ulcers (n=15), scleral ulcers (n=11), painful bullous keratopathy (n=8) and pterygium as an adjuvant to a conjunctival autograft (n=13). Cryo-preserved or freeze-dried amniotic membrane (AM) were used. The overall success rate, the interval to epithelialization, pain-subsiding time, and complications were evaluated. The pain relief and the full epithelialization interval in the bullous keratopathy patients given the cryo-preserved AM were compared with those given the freeze-dried AM. RESULTS: The success rate in the patients with neurotrophic ulcer, inflammatory corneal ulcer, scleral ulcer and bullous keratopathy were 93.3%, 66.7%, 92.9% and 100%, respectively. A conjunctival autograft with AMT showed a 100% success rate without recurrence. The time to re-epithelialization was 24.4+/-24.2, 20.4+/-5.8, and 16.9+/-7.0 days in patients with neurotrophic, inflammatory and scleral ulcers, respectively (p=0.431). The pain relief interval in the cryo-preserved and freeze-dried AM group was 17.7 and 23.3 days, and the re-epithelialization interval was 29 and 22 days, respectively, which was insignificant. CONCLUSIONS: AMT has a high success in the treatment of neurotrophic, scleral ulcer, bullous keratopathy and pterygium with a low rate of complications but presented only partial success in the treatment of inflammatory corneal ulcers. The clinical efficacy of AMT was not related to the methods used to preserve the AM.     

Coupling effects in bending, buckling and free vibration of generally laminated composite beams

A closed form expression to determine the effective flexural modulus of a laminated composite beam is developed and presented in this contribution. This effective flexural modulus is applied to the bending, buckling and free vibration response of generally laminated composite beams with various boundary supports. The expression was developed using the combination of the Euler–Bernoulli beam and classical lamination theory. In addition the results of an extensive finite element analysis are used to validate the analytical model. The comparison of the analytical results, the finite element results and the experimental results showed good correlation. It is also observed that coupling response is an important variable that must be included in the computation of the effective flexural stiffness of generally laminated beam.     

春之路

这个纪念方案拟建一条道路,以表达对2008年5·12四川大地震遇难者的沉痛哀悼.这条路毗邻四川省的某一河边,那里有一大片可循环利用的建筑废墟地,零星分布着小麦田.独特的场所体验由地下和地上两个项目组成.     

Surface-layer damage and responsivity in sputtered-ITO/p-GaN Schottky-barrier photodiodes

It is postulated that donor-like nitrogen vacancies, caused by the sputtering of a Schottky-barrier metal onto p-type gallium nitride, diffuse into the GaN and form a surface layer in which both the minority-carrier lifetime and mobility are drastically reduced. Such a damaged surface layer is shown to reduce the responsivity of p-GaN Schottky-barrier photodiodes, thereby offering an explanation for the responsivity values in the range of 0.03–0.04 A/W that have been measured in experimental ITO/p-GaN devices. On making allowance for the damaged surface layer, an electron diffusion length of around 300 nm can be inferred for the undamaged p-GaN region.     

Cognitive information delivery in geo‐location database based cognitive radio networks

For the problem of spectrum scarcity and wastage, cognitive radio (CR) technology provides a solution to utilizing the vacant spectrum more efficiently. As one of the most promising techniques to obtain the cognitive information in TV white spaces, geo‐location database approach has attracted a lot of recent attentions, with its goal of enhancing the efficiency of spectrum usage and avoiding the interference to TV receivers. However, existing works mainly focus on the construction and applications of geo‐location database, and seldom consider how to deliver the cognitive information from the database to TV band devices. In this paper, we investigate the tradeoff between increasing the accuracy of cognitive information delivery and reducing the overhead. We design two mesh fusion algorithms to reduce the redundancy of cognitive information and improve the efficiency of cognitive information delivery. Finally, we verify our analysis and evaluate the efficiency of the proposed mesh fusion algorithms through numerical studies. Copyright © 2016 John Wiley & Sons, Ltd.     

Experimental and computational studies of multiphase hydrodynamics in a hydrocyclone separator system

The flow patterns within a hydrocyclone separator system have been studied experimentally using particle image velocimetry (PIV) and computationally via large eddy simulations (LES). Various aspects of the flow field such as the process of air core structure formation, pressure and velocity distributions within the system have been characterized. Detailed flow field information in the form of velocity vector maps of entire planes have been obtained experimentally and reproduced computationally. Good qualitative agreements between velocity vector fields, air core structure and averaged velocity distributions have been achieved. LES is deemed to be an adequate methodology for modelling the air core structure and flow patterns of the surrounding liquid in a hydrocyclone separator system.     

Brønsted Base‐Catalyzed Tandem Isomerization–Michael Reactions of Alkynes: Synthesis of Oxacycles and Azacycles

An efficient synthesis of oxacycles and azacycles was developed using a Brønsted base‐catalyzed tandem alkyne isomerization–Michael reaction sequence. Functionalized 2‐alkylidenetetrahydrofurans were prepared by an intramolecular oxy‐Michael reaction on an allene that was generated in situ from an alkynoate. The aza‐Michael version using alkynylamines, alkynylamides and alkynyl carbamates led to piperidines, lactams and oxazolidinones, respectively. An enantioselective version of this reaction resulted in an axially chiral lactam with high enantioselectivity. Some alkynes, however, were unable to complete the intramolecular Michael reactions and provided enantioenriched allenes.