An extended artificial bee colony with local search for solving the Skyline-based web services composition under interval QoS properties

In this paper, we introduce an extended version of artificial bee colony with a local search method (EABC) for solving the QoS uncertainty-aware web service composition (IQSC) problem, where the ambiguity of the QoS properties are represented using the interval-number model. At first, we formulate the addressed problem as an interval constrained single-objective optimization model. Then, we use the skyline operator to prune the redundant and dominated web services from their sets of functionally equivalent ones. Whereas, EABC is employed to solve the IQSC problem in a reduced search space more effectively and more efficiently. For the purpose of validation of the performance and the efficiency of the proposed approach, we present the experimental comparisons to an existing skyline-based PSO, an efficient discrete gbest-guided artificial bee colony and a recently provided Harris Hawks optimization with an elite evolutionary strategy algorithms on an interval extended version of the public QWS dataset.

Performance enhancement of an MRE-based isolator using a multi-layered electromagnetic system

A magnetorheological elastomer (MRE) is one of smart materials which can control the stiffness according to a strength of a magnetic field. In this regard, various types of MRE-based isolators have been studies. However, there was a limit to performance validation due to the material and structural limitations. In this study, an optimal mixing ratio of the MRE was considered and a new type of an electromagnetic system was proposed. A multi-layered electromagnetic system was proposed to constantly maintain a magnetic closed circuit by behaving with the deformation of the MRE. Through this, numerical and experimental comparisons were performed with the conventional MRE-based isolator, and the superiority of the proposed MRE-based isolator was validated. Moreover, the dynamic characteristics of the proposed MRE-based isolator under the vertical load were investigated. The results show that the proposed MRE-based isolator outperforms the conventional MRE-based isolator in improving the MR effects and the dynamic characteristics of the proposed MRE-based isolator under the vertical load were identified.

An Improved K-Means Algorithm Based on Evidence Distance

The main influencing factors of the clustering effect of the k-means algorithm are the selection of the initial clustering center and the distance measurement between the sample points. The traditional k-mean algorithm uses Euclidean distance to measure the distance between sample points, thus it suffers from low differentiation of attributes between sample points and is prone to local optimal solutions. For this feature, this paper proposes an improved k-means algorithm based on evidence distance. Firstly, the attribute values of sample points are modelled as the basic probability assignment (BPA) of sample points. Then, the traditional Euclidean distance is replaced by the evidence distance for measuring the distance between sample points, and finally k-means clustering is carried out using UCI data. Experimental comparisons are made with the traditional k-means algorithm, the k-means algorithm based on the aggregation distance parameter, and the Gaussian mixture model. The experimental results show that the improved k-means algorithm based on evidence distance proposed in this paper has a better clustering effect and the convergence of the algorithm is also better.

Extended PKM Fixturing System for Micro-Positioning and Vibration Rejection in Machining Application

The paper aims to present a mechatronic device able to micro-position the workpiece and to reject disturbances due to machining operation. A decoupling method is proposed for a parallel kinematic machine (PKM) fixturing platform composed by a 3-DoF flexure-based piezo-actuated mechanism. The parallel platform, with a vertical motion and two rotations, is described and its kinematics and dynamics are studied. The coupling undesirable effect is investigated based on a set of poses. To improve the quasi-static regulator model for a set-point following system, a bump less switching controller and a fine-tuning procedure, to estimate the parameter uncertainty and enable the external disturbance containment in an extended broadband frequency range, are presented. The platform and the piezo-actuator controllers are modelled based on a gain scheduling, standard ISA form method, to guarantee the stability. The accuracy is demonstrated through a set of simulations and experimental comparisons. A sensitivity analysis that evaluates the tracking performance and the disturbance rejection based on the number of signal amplitudes, frequencies, and phases is discussed. A validation phase has shown that the developed architecture presents a steady state error lower than 1.2 µm, a vibration reduction of 96% at 1130 Hz with a maximum resolving time of 6.60 ms.

Shared projects and symbiotic collaborations: Shenzhen and London in comparative conversation

This paper presents ‘shared projects’ and the ‘symbiotic’ relations they engender to capture accounts of state and society actors collaborating to turn individual constraints into collective opportunities for pursuing urban experiments which are institutionally-shaped but also institution-shaping. The concepts are developed through a sequential and recursive comparison – that is, a ‘comparative conversation’– between a case of urban village upgrading in Shenzhen and Community Land Trust Development in London. The paper uses a pragmatist approach to capitalist transformation as a starting point for comparison between these supposedly ‘incomparable’ cases. I build both heterogeneous and generalisable accounts of the pathways and progressive potential of collaborations on shared projects by recursively composing analytical proximities across the cases and their contexts of state entrepreneurialism and austerity localism. Theoretically, this paper contributes to scholarship which focuses on the contingency and complexity inherent in urban transformation. State and society actors are seen as potential collaborators working pragmatically to solve systemic problems without necessarily targeting wholesale systemic change. Methodologically, it contributes to ongoing attempts to demonstrate the positive relationship between experimental comparisons and conceptual innovation through staging a ‘comparative conversation’.