以TRIZ进化理论为基础的产品技术预测支持系统研究

产品技术预测是使企业保持长久竞争优势的有效方法之一,而TRIZ的技术进化理论恰恰是众多产品技术预测理论中最具优势和生命力的。以TRIZ的技术进化理论为基础,运用先进的计算机软件编程技术--基于Windows2000环境, 以Visual Basic 6.0为开发语言,Access作为后台数据库,采用DAO数据库访问技术,构建了基于TRIZ进化理论的产品技术预测支持系统。该系统由8个模块组成,分别是系统维护、待预测产品数据库、产品技术成熟度预测、技术进化路线分析、技术进化知识库、工程报表、编辑和学习帮助模块,通过系统的应用可以实现产品技术成熟度的预测分析,为产品提供可能的技术进化模式或进化路线,将以前手工完成的工作软件化,从而使企业快速、准确地把握产品的技术走向,实现产品和技术的创新。     

Weighted least-square estimation of demand product mix and its applications to semiconductor demand

Estimation of demand product mix is important for effective production plans. Unlike most research in the literature where the product mix is either given or treated as a decision variable in optimization of the production efficiency, this paper focuses on the product mix itself and how to estimate it from the market demand. With more accurate information on the demand product mix, aggregate production plans for product families can be disaggregated into quality detailed plans for individual product items. In this paper, least-square estimates of demand product-mix proportions are first derived. To take into account the effect of the product life cycle, dynamic weighting schemes are then developed to improve the accuracy of the product-mix estimates. For applications, we concentrate particularly on semiconductor demand where new generations of semiconductor products emerge at the pace of every six months, as manifested by the celebrated Moore's laws. The proposed methodologies will be tested with simulated DRAM demands and actual semiconductor demands of different technology generations.     

Development of a production cost estimation framework to support product family design

The main task of a product family designer is to decide the right components/design variables to share among products to maintain economies of scale with minimum sacrifice in the performance of each product in the family. The decisions are usually based on several criteria, but production cost is of primary concern. Estimating the production cost of a family of products involves both estimating the production cost of each product in the family and the costs incurred by common and variant components/design variables in the family. To estimate these costs consistently and accurately, we propose a production cost estimation framework to support product family design based on activity-based costing (ABC), which consists of three stages: (1) allocation, (2) estimation, and (3) analysis. In the allocation stage, the production activities and resources needed to produce the entire products in a family are identified and classified with an activity table, a resource table, and a production flow. To help allocate product data for production, a product family structure is represented by a hierarchical classification of products that form the product family. In the estimation stage, production costs are estimated with cost estimation methods selected based on the type of information available. In the analysis stage, components/design variables possible for product family design are investigated with resource sharing methods through activity analysis. As an example, the proposed framework is applied to estimate the production cost of a family of cordless power screwdrivers that share different components within the family.     

数字演化硬件的函数级在线进化技术研究

采用基于现场可编程门阵列(FPGA)模型的数字电路函数级在线自适应进化方法,提出了一种新的有效的进化策略:根据目标电路的功能组成将目标电路分解为多个子模块单元,然后对多个子模块单元分别进行进化设计,再利用子模块单元进行预期目标数字电路的在线进化,以降低每一级进化的染色体长度和提高收敛速度.以4×2乘法器电路为例,用这种方法成功实现了数字电路在线进化,结果表明,与逻辑门级进化方法相比,该方法改善了在线进化时存在染色体过长、收敛速度缓慢、测试评估困难的状况,收敛速度提高了5倍左右.     

Rolling horizon,multi-product production planning with chance constraints and forecast evolution for wafer fabs

In this paper, we study production planning models for semiconductor wafer fabrication facilities (wafer fabs) that consider both safety stocks at the finished goods inventory level and workload-dependent lead times. The evolution of demand forecasts over time follows the multiplicative Martingale Model of Forecast Evolution (MMFE) for multiple products and is incorporated into the planning models via shortfall-based chance constraints, permitting the simultaneous determination of production quantities and safety stocks. We study two variants of this formulation, one that considers forecast updates and one that does not. A planning model with workload-dependent lead times that does not consider safety stocks is used for comparison. The performance of the planning models is assessed in a rolling horizon environment using a simulation model of a scaled-down wafer fab. We find that the chance-constrained model with forecast updates outperforms the one without forecast updates with respect to expected service level and profit. Both chance-constrained models outperform the model without safety stocks. These results indicate that considering forecast evolution in production planning models can lead to improved performance by exploiting the advance demand information provided by the forecast updates.     

Exploration,exploitation and innovation performance: disentangling the evolution of industry

The evolution of industry has recently attracted the attention of scholars studying the relationships between exploration and exploitation strategies and innovation performance. Surprisingly, although extant research has already acknowledged its multidimensional character, it has only been analyzed in an aggregate fashion. In this paper, we distinguish two components of the evolution of industry, the pace of market evolution and the pace of technology evolution, and we elaborate on their different impacts in the context of exploration and exploitation strategies. More precisely, we argue that while a rapid pace of technology evolution has opposite impacts on the relationships between exploration (positive), exploitation (negative) and innovation performance, a rapid pace of market evolution positively affects both exploration and exploitation. Our findings provide substantial support for our prediction using a large panel of Spanish innovating firms for the period 2008–2012.     

RMS capacity utilisation: product family and supply chain

The paper contributes to development of RMS through linkage with external stakeholders such as customers and suppliers of parts/raw materials to handle demand fluctuations that necessitate information sharing across the supply chain tiers. RMS is developed as an integrated supply chain hub for adjusting production capacity using a hybrid methodology of decision trees and Markov analysis. The proposed Markov Chain model contributes to evaluate and monitor system reconfigurations required due to changes of product families with consideration of the product life cycles. The simulation findings indicate that system productivity and financial performance in terms of the profit contribution of product-process allocation will vary over configuration stages. The capacity of an RMS with limited product families and/or limited model variants becomes gradually inoperative whilst approaching upcoming configuration stages due to the end of product life cycles. As a result, reconfiguration preparation is suggested quite before ending life cycle of an existing product in process, for switching from a product family to a new/another product family in the production range, subject to its present demand. The proposed model is illustrated through a simplified case study with given product families and transition probabilities.     

The bayesian approach to the combination of forecasts: Some extensions into a Skewed environment

Where a decision-maker has to rely on expert opinions a need for a normative model to combine these forecasts appears. This can be done using Bayes' formula and by making some assumptions on the prior distribution and the distribution of the expert assessments. We extend the case to skewed distributions of these assessments. By using an Edgeworth expansion of the density function including the skewness parameter, we are able to obtain the formula to combine the forecasts in a Bayesian way.      

集成鱼骨分析与进化法则的产品失效预测及问题求解

 基于传统FMEA在失效问题分析与解决方面的不足,提出了一种集成鱼骨图、FMEA和进化法则的创新设计方法．利用鱼骨图层次化分析辅助FMEA全面挖掘可能发生的失效模式,按照FMEA的规范表达分析失效模式并确定风险优先指数RPN,然后运用进化法则针对失效问题进行有效的解决,提高了解决问题的效率．最后通过铁路减振的示例验证了该集成方法的可行性．     

Joint decision of product configuration and remanufacturing for product family design

Product family design (PFD) is a popular method for increasing product variety to satisfy the needs of diversified markets. With the increasing concern for environmental friendliness in society, more and more companies develop launching remanufactured products and include them in their product families. Therefore, PFD should be considered in a broad decision space where configuration of product variants and remanufacturing are considered simultaneously. However, this issue was not addressed properly in previous research. In this paper, a methodology for joint decision of product configuration and remanufacturing is proposed in which a bi-objective mixed integer programming model is formulated to determine the configurations of both new and remanufactured products for minimising product cost, maximising total market share, and satisfying reliability requirements. Then, Non-dominated Sorting Genetic Algorithm II (NSGAII) is adopted to solve the optimization problem. Computational experiments were conducted and their results show that NSGAII is convergent to the model well. A case study is presented to illustrate the applicability and effectiveness of the proposed methodology.     

基于差分进化的时变信道最大似然估计算法

研究了隧道环境下的通信信道估计。针对隧道环境的地铁列车与轨旁设备之间无线通信中无线传输信道快速变化的特点,提出了一种采用元胞差分进化(DE)方法实时获取时变信道的有效信道长度的新型最大似然(ML)信道估计算法——DE-ML算法。仿真结果表明该算法在使用较少导频信息的情况下,通过差分进化方法有效估计跟踪有效信道长度,其估计性能优于最小二乘(LS)、线性最小均方误差(LMMSE)、传统ML等经典信道估计算法。该算法能在提高系统传输效率的同时显著提高算法的估计精度,尤其在高速移动情况下也具有了非常良好的性能。     

Modeling of damage evolution in soft-wood perpendicular to grain by means of a discrete element approach

The anisotropy of wood within the radial–tangential (RT) growth plane has a major influence on the cracking behavior perpendicular to grain. Within the scope of this work, a two-dimensional discrete element model is developed, consisting of beam elements for the representation of the microstructure of wood. Molecular dynamics simulation is used to follow the time evolution of the model system during the damage evolution in the RT plane under various loading conditions. It is shown that the results are in good agreement with experiments on spruce wood, and that the presented discrete element approach is applicable for detailed studies of the dependence of the microstructure on mesoscopic damage mechanism and dynamics of crack propagation in microstructured and cellular materials like wood.     

A multi-objective model for multi-project scheduling and multi-skilled staff assignment for IT product development considering competency evolution

We address a multi-skill project scheduling problem for IT product development in this article. The goal is for product development managers to be able to generate an initial schedule at an early stage of development activities. Due to the complexity of the product structure and functionality, an IT product development effort is divided into multiple projects. Each project includes several tasks, and each task must be completed by an employee who has mastered a certain skill to complete it. A pool of multi-skilled employees is available, and the employees’ skill efficiencies are influenced by both learning and forgetting phenomena. Based on the real-world demands of product development managers, three objectives are simultaneously considered: skill efficiency gain, product development cycle time and costs. To solve this problem, we propose a multi-objective non-linear mixed integer programming model. The Non-dominated Sorting Genetic Algorithm II (NSGA-II)is designed to generate an approximation to the optimal Pareto front of this NP-hard multi-objective optimisation problem. The algorithm produces feasible schedules for all the development projects using the serial schedule generation scheme. We adopt penalty values and individual employee adjustments to address resource conflicts and constraint violations. A weighted ideal point method is used to select the final solution from the approximate Pareto solution set. An application case of a new electrical energy saving product implementation in a leading electrical device company in China is used to illustrate the proposed model and algorithm.     

面向产品族的客户需求最佳聚类确定方法

以大规模定制为前提,为实现客户需求指导产品族规划的目的,建立了客户需求广义聚类模型．根据客户需求信息是否存在层次等级关系将其划分为递阶型和等价型,针对目前对递阶型客户需求聚类研究不能充分利用需求信息的问题,提出了基于模糊集的混合型客户需求聚类算法,增强了处理需求信息的能力．为实现产品族的合理规划,综合客户满意度和企业成本理想度建立可行性指标,提出了基于可行性确定客户需求最佳聚类的方法,并以最佳聚类方案指导产品族规划,在满足客户需求的同时保证了企业宽松的资金链．最后结合实例说明了该方法的实用性．     

Insight into atmospheric corrosion evolution of mild steel in a simulated coastal atmosphere

The corrosion behavior of mild steel in a simulated coastal atmosphere environment has been investigated by the indoor accelerated wet/dry cyclic corrosion acceleration test(CCT),scanning electron microscopy(SEM),Raman spectroscopy and electrochemical measurements.During the CCT test of 60 cycles,the evolution of logarithmic(corrosion rate)vs.logarithmic(CCT cycles)presents a turning point at the 5th cycle,presenting a tendency to increase first and then decrease to gradually stabilize as the CCT cycle prolonged.Before the 5th cycle,γ-FeOOH and β-FeOOH and Fe3O4 were detected,respectively.And then,α-FeOOH as a new chemical composition was detected in the subsequent corrosion cycles.It is found that,after long term corrosion,the rust separated into a relatively dense inner layer rich with α-FeOOH and a loose outer layer rich with γ-FeOOH,both of which have poor electrical conductivity.The rapid increase of corrosion rate in the early stage since reducible corrosion products are involved in the reduction process of the cathode which promotes the dissolution of the anodic metal substrate.Afterward,as the rust layer thickens,the resistance of the rust increases,and the aggressive ions diffusion is blocked,gradually suppressing the electrochemical corrosion process.At last,when the composition and distribution of the rust layer remain stable,the corrosion presents a fluctuating speed around a certain value during the cracking and self-repairing process of the rust layer.     

Simulation and performance evaluation of partially and fully integrated sales and operations planning

This article presents rolling horizon simulation models and performance analysis of partially and fully integrated sales and operations planning (S&OP) against traditional decoupled planning in a multi-site make-to-order (MTO) based manufacturing supply chain. Three simulation models are developed illustrating, respectively, the fully integrated S&OP model, which integrates cross-functional planning of sales, production, distribution, and procurement centrally; the partially integrated S&OP model, in which the joint sales and production planning is performed centrally while distribution and procurement are planned separately at each site; and the decoupled planning model, in which sales planning is carried out centrally while production, distribution, and procurement are planned separately and locally. A solution procedure is provided for each model so that a more realistic planning process can be simulated. Performances of rolling horizon simulation models are evaluated against those of the fixed horizon deterministic models. The results demonstrate that while deterministic models are important for theoretical studies, they are insufficient for decision support and performance evaluations in a real business environment. A rolling horizon simulation model is required to provide more realistic solutions. The effects of demand uncertainties and forecast inaccuracies are incorporated in the evaluation. The study is carried out based on a real industrial case of a Canadian-based oriented strand board (OSB) manufacturing company.     

Insight into the fracture evolution behavior of pre-flawed hollow-cylinder granite under multi-stage increasing-amplitude cyclic loads: A lab-scale testing

The structural deterioration and associated fracture evolution behavior of pre-flawed hollow-cylinder granite subjected to multi-stage increasing-amplitude (MSIA) cyclic loads are studied herein. The influences of rock structure on volumetric deformation, damage accumulation, energy dissipation, and failure pattern were investigated. It is shown that the volumetric deformation is relatively large for rock having high flaw angle, and it is the minimum and maximum for rock having a 10° and 70° flaw angle. A damage evolution model that can describe a first fast and then steady damage propagation was proposed based on the irreversible axial strain. Much energy needs to be consumed to drive crack propagation and hole collapse for rock having high angle flaws. A series of 2D computed tomography (CT) images reveal the different crack network pattern and how it is affected by the rock structure. A more complicated crack network is found for rock having a high flaw angle.     

A hybrid differential evolution and estimation of distribution algorithm based on neighbourhood search for job shop scheduling problems

Job shop scheduling problem (JSSP) is a typical NP-hard problem. In order to improve the solving efficiency for JSSP, a hybrid differential evolution and estimation of distribution algorithm based on neighbourhood search is proposed in this paper, which combines the merits of Estimation of distribution algorithm and Differential evolution (DE). Meanwhile, to strengthen the searching ability of the proposed algorithm, a chaotic strategy is introduced to update the parameters of DE. Two mutation operators are adopted. A neighbourhood search (NS) algorithm based on blocks on critical path is used to further improve the solution quality. Finally, the parametric sensitivity of the proposed algorithm has been analysed based on the Taguchi method of design of experiment. The proposed algorithm was tested through a set of typical benchmark problems of JSSP. The results demonstrated the effectiveness of the proposed algorithm for solving JSSP.     

The evolution of developmental patterning under genetic duplication constraints

Of considerable interest are the evolutionary and developmental origins of complex, adaptive structures and the mechanisms that stabilize these structures. We consider the relationship between the evolutionary process of gene duplication and deletion and the stability of morphogenetic patterns produced by interacting activators and inhibitors. We compare the relative stability of patterns with a single activator and inhibitor (two-dimensional system) against a ‘redundant’ system with two activators or two inhibitors (three-dimensional system). We find that duplication events can both expand and contract the space of patterns. We study developmental robustness in terms of stochastic escape times from this space, also known as a ‘canalization potential’. We embed the output of pattern formation into an explicit evolutionary model of gene duplication, gene loss and variation in the steepness of the canalization potential. We find that under all constant conditions, the system evolves towards a preference for steep potentials associated with low phenotypic variability and longer lifespans. This preference leads to an overall decrease in the density of redundant genotypes as developmental robustness neutralizes the advantages of genetic robustness.