Design of diffractive phase elements that produce focal annuli: a new method

A new optimization method based on the general theory of amplitude-phase retrieval is proposed for designing the diffractive phase elements (DPE's) that produce focal annular patterns. A set of equations for determining the phase distribution of the DPE is given. The profile of a surface-relief DPE can be designed with an iterative algorithm. Numerical calculations are carried out for several examples. A comparison of the performance of the DPE's designed with the Gerchberg-Saxton algorithm and the new algorithm is presented. The effect of quantization of the phase distribution of the DPE's on the results is also investigated. The results show that the new algorithm can successfully achieve the design of the DPE's that convert the uniform incident beam into the focal annular patterns.     

A selection of material using a novel type decision-making method: Preference selection index method

The aim of the current study is to implement a novel tool to help the decision-maker for selection of a proper material that will meet all the requirements of the design engineers. Preference selection index (PSI) method is a novel tool to select best alternative from given alternatives without deciding relative importance between attributes. In the present study, three different types of material selection problems are examined. A validation and consistency test of preference selection index method is performed in present work by comparing results of PSI method with published results of graph theory and matrix approach (GTMA), and technique for order preference by similarity to ideal solution (TOPSIS) method, respectively. The research has concluded that the PSI method is logical and more appropriate for the material selection problems.     

A solution selection approach to multiresponse surface optimization based on a clustering method

In Multi-Response Surface Optimization (MRSO), responses are often in conflict. To obtain a satisfactory compromise, the preference information of a Decision Maker (DM) on the tradeoffs among the responses should be considered. One of the promising alternatives is a posterior preference articulation approach. It first generates nondominated solutions and then makes the DM select the best one from the nondominated solutions. In this article, a solution selection approach is presented. It takes the posterior approach and employs a clustering method to aid the selection process of the DM. The DM can obtain the satisfactory compromise solution easily by the proposed method.     

复杂系统的设计认知和创新

目的研究复杂系统设计过程中设计师的设计认知和设计创新行为。方法通过国内外相关文献的研究和分析,总结归纳复杂系统设计问题界定和解决方案构思的认知过程、复杂系统创新设计构思的生成机制、复杂系统的创新设计策略,分析复杂系统设计认知和创新研究领域将发生的变革和未来发展的趋势。结论系统探讨了复杂系统设计认知与创新过程中的设计问题界定和解决方案构思的联合演化机制、给定和自发性解决方案示例,给设计师带来的认知固化和类比推理创新启发作用、结构化和机会主义的创新设计策略,发现当下的复杂系统创新设计理论和实践研究,还需要进一步开展跨学科知识融合激励的复杂系统创新设计研究,与此同时,加强关于设计师主观认知不确定性的定量建模研究,从而更好、更有针对性地探究复杂系统创新设计中认知过程的自然本质。     

Vendor selection in a modified re-buy situation using a strategy-aligned fuzzy approach

The supplier/vendor selection is a decision-making problem at the strategic management level that involves a semi-structured process. The majority of the existing approaches obtained their optimal solutions without considering their fits with the strategy of the firm. This study utilizes the supplier positioning matrix, modified from the product-process change matrix, to link the capability of suppliers with the requirements of the customers to identify the strategy-aligned criteria for vendor selection in a modified re-buy situation. A fuzzy factor rating system is then used to evaluate the potential vendors based on the type of components required by the customers. In addition, in the proposed model, the final decision-maker is given the authority to synthesize the scores of individual alternatives based on the risks of individual vendors to accommodate the differences among the vendors to the specific environment. An empirical case study is performed to demonstrate the efficacy of the proposed system and to identify the best potential vendor(s) for further negotiation and development. The results of the case study also provide interesting managerial implications.     

Enhancing multivariate pattern analysis for magnetoencephalography through relevant sensor selection

While the popularity of multivariate pattern classification is growing rapidly in magnetoencephalography (MEG) data analysis, the analysis pipelines used by the neuroscience community are still missing some fundamental machine-learning techniques and principles that would increase their effectiveness. Here, we show that MEG decoding accuracy improves significantly with the addition of feature selection methods to the analysis pipeline. We compare one unsupervised and two supervised feature reduction methods in the current study. Our results show that supervised feature selection methods like statistical dependency and mutual information improve decoding performance and attain higher session-to-session reliability compared to unsupervised dimensionality reduction methods like principal component analysis. Furthermore, we demonstrate that the selected sensors in the data related to a visual task at each time point are consistent with the pattern reflecting the sweep of information in the ventral visual pathway.     

Exact flow of a third grade fluid past a porous plate using homotopy analysis method

The flow of a third grade fluid past a porous plate is considered. An exact analytical solution of the governing non-linear differential equation is constructed using homotopy analysis method. It is observed that the relevant perturbation solution corresponds to a special case of the presented solution.     

应用优化的同伦分析法求解非线性Jerk方程

应用优化的同伦分析法计算了具有三次非线性项的三阶微分方程(Jerk)的近似周期和近似解析周期解。文中给出一个算例说明由优化的同伦分析法可以容易得到精确的二阶近似周期解。当初速度 比较大时,一阶近似周期与精确周期的百分比误差为-0.415%,而二阶近似周期与精确周期的百分比误差为-0.0298%。与数值方法给出的“精确”周期解比较,一阶近似解析周期解和二阶近似周期解的精度很高。这个说明同伦分析法对求解非线性Jerk方程非常有效     

Design space optimization using a numerical design continuation method

A generalized optimization problem in which design space is also a design to be found is defined and a numerical implementation method is proposed. In conventional optimization, only a portion of structural parameters is designated as design variables while the remaining set of other parameters related to the design space are often taken for granted. A design space is specified by the number of design variables, and the layout or configuration. To solve this type of design space problems, a simple initial design space is selected and gradually improved while the usual design variables are being optimized. To make the design space evolve into a better one, one may increase the number of design variables, but, in this transition, there are discontinuities in the objective and constraint functions. Accordingly, the sensitivity analysis methods based on continuity will not apply to this discontinuous stage. To overcome the difficulties, a numerical continuation scheme is proposed based on a new concept of a pivot phase design space. Two new categories of structural optimization problems are formulated and concrete examples shown. Copyright © 2001 John Wiley & Sons, Ltd.     

Prioritising technical attributes in QFD under vague environment: a rough-grey relational analysis approach

This study aims at improving the effectiveness of Quality function deployment (QFD) in handling the vague, subjective and limited information. QFD has long been recognised as an efficient planning and problem-solving tool which can translate customer requirements (CRs) into the technical attributes of product or service. However, in the traditional QFD analysis, the vague and subjective information often lead to inaccurate priority. In order to solve this problem, a novel group decision approach for prioritising more rationally the technical attributes is proposed. Basically, two stages of analysis are described: the computation of CR importance and the prioritising the technical attributes with a hybrid approach based on a rough set theory (RST) and grey relational analysis (GRA). The approach integrates the strength of RST in handling vagueness with less priori information and the merit of GRA in structuring analytical framework and discovering necessary information of the data interactions. Finally, an application in industrial service design for compressor rotor is presented to demonstrate the potential of the approach.     

Vendor selection problem: a multi-criteria approach based on strategic decisions

Many factors in the current scenario have influenced manufacturing organisations to have a competitive edge by concentrating on entire supply chains. Sourcing decisions are one of the strategic decisions because they enable companies to reduce costs and improve profit figures. The main task in sourcing is vendor selection. Recent challenges such as shortened product life cycle, just-in-time environment, and the importance of strategic partnerships in upstream chains always influence companies to prioritise vendor selection. In addition, outsourced parts and components account for a significant contribution in the cost of finished goods. Thus evaluating and selecting the right vendor is the key to business. Vendors are selected merely on the basis of cost factors in the traditional approach. However, companies eventually have understood that their approach which emphasises costs as the sole criterion is inefficient and needs to be changed. To deal with the complex process of vendor evaluation, multiple criteria decision-making techniques have evolved. This study presents the integrated approach of multiple multi criteria decision making (MCDM) techniques such as fuzzy logic, strength-weakness-opportunity-threat (SWOT) analysis, and data envelopment analysis. The efficacy of the proposed approach is evident from the case study of an automotive component manufacturer involving 20 vendors, comprising of pre-qualification by fuzzy SWOT and final selection by DEA.     

Design of a composite beam using the failure probability‐safety factor method

The paper shows the practical importance of the failure probability‐safety factor method for designing engineering works. The method provides an automatic design tool by optimizing an objective function subject to the standard geometric and code constraints, and two more sets of constraints, that guarantee some given safety factors and failure probability bounds, associated with a given set of failure modes. Since a direct solution of the optimization problem is not possible, the method proceeds as a sequence of three steps: (a) an optimal classical design, based on given safety factors, is done, (b) failure probabilities or bounds of all failure modes are calculated, and (c) safety factors bounds are adjusted. This implies a double safety check that leads to safer structures and designs less prone to wrong or unrealistic probability assumptions, and to excessively small (unsafe) or large (costly) safety factors. Finally, the actual global or combined probabilities of the different failure modes and their correlation are calculated using a Monte Carlo simulation. In addition, a sensitivity analysis is performed. To this end, the optimization problems are transformed into another equivalent ones, in which the data parameters are converted into artificial variables. In this way, some variables of the dual associated problems become the desired sensitivities. The method is illustrated by its application to the design of a composite beam. Copyright 2004 © John Wiley & Sons, Ltd.     

基于频响函数综合的舱筏隔振系统灵敏度分析和优化＊

利用频响函数综合方法,推导了浮筏隔振系统连接点的位移,给出基座上的力和输入到基座的功率流对浮筏隔振系统的上、下层隔振器的刚度和阻尼的设计灵敏度表达式,并分别以最小化某一频段内输入到基座的功率流和传递到基座的力的均方值为优化目标,结合灵敏度分析方法,对上、下层隔振器的刚度进行了优化.优化结果表明,基于子结构灵敏度分析的方法是一种有效的优化方法,以最小化传递到基座的力的均方值为优化目标得到的隔振器的最优刚度不能同时使输入到基座的功率流有很大的衰减.     

An algebraically partitioned FETI method for parallel structural analysis: performance evaluation

This paper presents the algorithmic performance of an algebraically partitioned Finite Element Tearing and Interconnection (FETI) method presented in a companion paper. A simple structural assembly topology is employed to illustrate the implementation steps in a Matlab software environment. Numerical results indicate that the method is scalable, provided the iterative solution preconditioner employs the reduced interface Dirichlet preconditioner. A limited comparison of the present method with the differentially partitioned FETI method with corner modes is also offered. Based on this comparison and a reasonable extrapolation, we conclude the present algebraically partitioned FETI method possesses a similar iteration convergence property of the differentially partitioned FETI method with corner modes. © 1997 John Wiley & Sons, Ltd.     

An algebraically partitioned FETI method for parallel structural analysis: algorithm description

An algebraically partitioned FETI method for the solution of structural engineering problems on parallel computers is presented. The present algorithm consists of three attributes: an explicit generation of the orthogonal null-space matrix associated with the interface nodal forces, the floating subdomain rigid-body modes computed from the subdomain static equilibrium equation of the classical force method and the identification of redundant interface force constraint operator that emanates when the interface force computations are localized. Comparisons of the present method with the previously developed differentially partitioned FETI method are offered in terms of the saddle-point formulations at the end of the paper. A companion paper reports implementation details and numerical performance of the proposed algorithm. © 1997 John Wiley & Sons, Ltd.     

光伏组件运输包装的设计和有限元分析

针对目前铝合金边框光伏组件的运输包装中存在的不足,以规格为1665mm×1000mm×50mm的组件为例,综合考虑了客户要求、产品特性、包装成本、包装效率和产品保护性等因素,设计了一种更为合理的运输包装方案。在方案的内包装中,设计了一种用于固定和分隔组件的塑料围框。利用ANSYS Workbench软件,参考ISTA 3E实验中的底楞跌落试验,进行了围框和组件的瞬态响应有限元分析。结果显示,围框能够维持包装的稳定性和安全性。     

Factors that determine a Patient's willingness to physician selection in online healthcare communities: A trust theory perspective

Health care users and patients are increasingly using online health communities to seek medical service, especially during the COVID-19 epidemic. The factors that determine the online trust between physicians and patients perplex the stakeholders for a long time. Based on the trust theory, this study explored the influence of physicians' personal quality and online reputation on patients' selection. A longitudinal panel data collection exercise, covering 11905 physicians on haodf. com, was conducted on May 20, 2018, May 22, 2019 and May 25, 2020. The random effect models are used to test our hypothesis. Results show that physicians' quality (competence, benevolence, and integrity) and online reputation (online reviews and online rating) can significantly affect patients' selection. Moreover, the physician's gender can enhance the influence of online reputation on patients' selection. As online healthcare community becomes an increasingly appealing channel for health, the frequency of the physician's quality information updating and the quality of online service are equally important to online physician-patient trust.     

Enterprise risk management: a DEA VaR approach in vendor selection

Enterprise risk management (ERM) has become an important topic in today's more complex, interrelated global business environment, replete with threats from natural, political, economic, and technical sources. The development and current status of ERM is presented, with a demonstration of how risk modelling can be applied in supply chain management. Within supply chain management, a major managerial decision is vendor selection. We start with discussion of the advanced ERM technology, i.e. value-at-risk (VaR) and develop DEA VaR model as a new tool to conduct risk management in enterprises. A vendor selection set of data is used to demonstrate how this model can be used to assess supply risks in ERM. Such models provide means to quantitatively improve decision making with respect to risk.