Explore the vast range of titles available.

A dimensional synthesis method for a spatial RCCC rigid-body guidance mechanism that satisfies non-periodic design requirements is proposed. By solving the 21-dimensional spatial RCCC mechanism motion generation problem in five steps, the dimension of the numerical atlas database is effectively reduced. The installation angle parameters, link twists, link lengths and link offset are matched using the established numerical atlas database. The mechanism geometric parameters obtained from the database are then optimized using a genetic algorithm. On this basis, the equations for calculating the actual sizes and installation position parameters of the objective mechanism are established; thus, the spatial RCCC mechanism motion generation with non-periodic design requirements is realized. Since there are fewer independent variables in each step of the proposed reduced dimensional synthesis method, the computational burden is smaller than existing numerical atlas method. Avoiding the solution of complex nonlinear equations, the method is therefore not limited by the number of prescribed positions compared with the analytical method. Moreover, since the problem of synchronous optimization of input angles and geometric parameters is avoided, the efficiency is far higher than optimization method. Two examples are presented to demonstrate the efficacy and accuracy of the proposed theory.

Pipe systems are broadly used in modern buildings and large transportation vehicles. The reduction of noise from pipes is one of the main concerns in their engineering applications. In this paper, the reduction of the radiated noise from pipes is studied experimentally using various attached structures. An experimental system is constructed in an anechoic room. Three types of attached structures are considered, including foam coatings, distributed absorbers and periodic absorbers. Via the comparison of basic pipe and pipes with different noise control designs, the reduction effects from the attached structures are compared and analysed. The results show that the radiated noise is effectively reduced by the foam coatings and distributed absorbers, especially, at most of the peaks of the noise. The distributed absorbers reduce the noise more on the whole. The low frequency peaks (below 200Hz) of the noise are reduced most by the periodic absorbers. Via the proper design of the structure types and corresponding parameters, the low frequency property, the broadband property and the reduction amplitude will be obviously enhanced.

How we designed this week's cover.

Glide-symmetric double-corrugated parallel-plate waveguides (GS-DCPPWs) have essential technical properties such as an electromagnetic bandgap, lower dispersion, and the ability to control the equivalent refractive index. For this reason, a fast and simple analysis and design of GS-DCPPW structures have great importance to improve related microwave systems. This paper introduces a novel design methodology based on the auxiliary functions of generalized scattering matrix (AFGSM) for the dimensional synthesis of GS-DCPPWs. We test the applicability of the AFGSM method on a variety of numerical examples to determine the passband/stopband regions of single and GS-DCPPWs before applying the design procedure. Certain design specifications are chosen, and unit cell dimensions are constructed in accordance with the proposed design technique. Three design scenarios are considered to assess the success of how well the design criteria can be met with the proposed method. The designed unit cells have been periodically connected in a various finite numbers to create periodic filters as a test application for adjusting the electromagnetic bandgap. The success of the periodic GS-DCPPW filters obtained with the proposed design strategy in meeting the specified design requirements has been tested using full-wave electromagnetic simulators (CST Microwave Studio and HFSS). The results indicate that the combined use of the equivalent transmission line circuit and the root-finding routine provided by the proposed method facilitates rapid, efficient, versatile, and approximate designs for corrugated parallel-plate waveguides. Moreover, the design methodology provides the viability of developing a minimal unit cell and a compact periodic filter performance with respect to the literature counterparts.

PurposeIt is desired to provide a diversified iterative scheme for solving the constrained solutions of the generalized coupled discrete-time periodic (GCDTP) matrix equations from the perspective of optimization.Design/methodology/approachThe paper considers generalized reflexive solutions of the GCDTP matrix equations by applying the Jacobi gradient-based iterative (JGI) algorithm, which is an extended variant of the gradient-based iterative (GI) algorithm.FindingsThrough numerical simulation, it is verified that the efficiency and accuracy of the JGI algorithm are better than some existing algorithms, such as the GI algorithm in Hajarian, the RGI algorithm in Sheng and the AGI algorithm in Xie and Ma.Originality/valueIt is the first instance in which the GCDTP matrix equations are solved applying the JGI algorithm.

As a common method for design and analysis of computer experiments (DACE), optimal Latin hypercube designs (OLHD) offer excellent space-filling properties but are computationally intensive with larger datasets. Techniques like translational propagational LHD (TPLHD) and improved translational propagational algorithm (iTPA) that compose near-optimal LHDs reduce computational cost with adequate space-filling properties but struggle with large, high-dimensional datasets as well. This study introduces cyclic latin hypercube design (CLHD) to address these challenges by arranging elements at regular intervals, applying a roll operation, and utilizing an enhanced stochastic evolutionary (ESE) algorithm for efficient near-optimal LHD construction. Performance comparisons with OLHD, iTPA, random LHD, and periodic LHD across various dataset sizes show that CLHD successfully reduces computational time and enhances space-filling properties, up to 49.4 % better than random LHD, 30.0 % better than iTPA, and 4.2 % better than periodic LHD. Consequently, CLHD is an efficient alternative for large, high-dimensional datasets where OLHD is infeasible.

Periodic/aperiodic sequences with low autocorrelation sidelobes are widely used in many fields, such as communication and radar systems. Besides the correlation property, the frequency stopband property is often considered in the sequence design when the systems work in a crowded electromagnetic environment. In this paper, we aim at designing periodic/aperiodic sequences with low autocorrelation sidelobes and arbitrary frequency stopbands, and propose an efficient algorithm named FFT (fast Fourier transform)-based conjugate gradient algorithm. To calculate the step size efficiently, a method based on Taylor series expansion is developed. By changing the number of FFT points, the proposed algorithm can be easily used to generate periodic/aperiodic sequences. Since the gradient and step size can be implemented by FFT operations and Hadamard product, the whole algorithm is computationally efficient and can be used to design very long sequences. Numerical experiments show that the proposed algorithm has better performance than the state-of-the-art algorithms in terms of the running time.

In a distributed ‘networked control system’ (NCS), multiple physical systems or agents are connected to their corresponding controllers through a shared packet-switched communication network. For such distributed NCS, periodic sampled controller design is unsuitable to handle packet-switched closed-loop control systems and a novel stochastic optimal adaptive event-sampled controller scheme is proposed in the application layer for each physical system or agent expressed as an uncertain linear dynamic system. Lyapunov stability analysis will be utilised to derive the event trigger condition. In addition, a network scheduling protocol is also required for such NCS. Traditional network scheduling protocols are unsuitable for such NCS since the behaviour of the physical systems is disregarded during the protocol design. Therefore in this study, a novel distributed network scheduling protocol via cross-layer approach is developed to improve the performance of distributed NCS by minimising an overall system cost function which consists of the information collected from both the event-triggered controller for each physical system in the application layer and the distributed scheduling protocol from the network layer. It will be demonstrated that the proposed co-design approach will not only allocate the network resources efficiently but also it will improve the performance of the overall distributed NCS. Simulation results are included to demonstrate the effectiveness of the proposed cross-layer co-design.

Find examples of editorial design, audiences for content, what forms the content takes, and how workflow is managed. This book provides a primer on the elements of editorial design that result in rich editorial experiences.

Publishers of contemporary magazines invest more and more money in developing innovative design for an increasingly design-literate reader. Innovation, however, must always be grounded in the underlying conventions of legibility to ensure loyal readership and economic success. Digital Magazine Design provides detailed descriptions of all the necessary rules of design, and uses these rules to cast a critical eye over a selection of contemporary high-street magazines. The second part of this volume, written by publishing students, demonstrates how the tools of design can be applied to the analysis and practice of contemporary magazine design. Through an understanding of the relationship between text, image and design, and the ability to make informed judgements, the student is able to critically evaluate all publishable material.