两相位交叉口左转车辆抢行的元胞自动机模型

为了解决道路两相位交叉口所存在的左转车辆抢行问题,避免造成严重交通冲突,首先分析了左转车辆抢行行为、路径抢行、以及与直行车辆到达冲突点的时间差相关的概率抢行,在考虑过街行人对抢行行为干扰的情况下,构建了车辆、行人耦合的双路径左转-直行冲突元胞自动机模型,通过计算机仿真分析研究了左转车辆抢行行为对交叉口通行能力的影响。结果表明,无过街行人时,左转车辆抢行使交叉口通行能力下降约5%;有过街行人干扰时,交叉口的通行能力则进一步降低10%～25%。研究结果可为提高道路交叉口服务水平、提高道路通行率和安全性决策提供参考。     

异质网络下含有相关系数的SIR传染病模型的建立和分析

在疾病传播过程中,染病者和易感者有多大的倾向接触是传染病是否流行的关键因素。为了研究相关系数在疾病传播过程中的动力学行为以及其对于传染病传播动力学特性的影响,将状态节点之间的相关系数作为动态变量,利用二元组的反卷积逼近方法,在异质网络上建立了含有相关系数的SIR传染病动力学模型,分析了系统平衡点的存在性,给出了染病者与易感者之间相关系数存在正值的条件。在泊松分布下,模拟出了平衡状态下相关系数的三维变化图。通过生物学意义,用概率的方法,给出了系统的最终规模。结果表明,通过分析含有相关系数的SIR传染病模型,得到SIR传染病模型复杂的动力学性态,即当染病者数量趋于零时,染病者与易感者之间的相关系数不为零。研究模型在控制传染病传播的动力学研究方面具有一定的参考价值。     

基于T-S模型的一类时滞非线性系统模型预测控制

针对具有状态时滞特性的非线性离散系统,利用线性矩阵不等式的方法和Lyapunov稳定性理论,研究了基于状态反馈的非线性系统模型预测控制问题。基于T-S模糊模型对非线性离散系统进行描述并给出一种"min-max"预测控制算法,采用模型预测控制与模糊理论相结合的方法,利用平行分布补偿的原理,通过在每一个采样时刻优化无穷时域的性能指标,来求解在范数有界条件下相应的状态反馈控制律,讨论了预测控制器的设计问题,分析了此设计问题的可解性,给出了状态反馈控制器基于线性矩阵不等式的设计算法,保证了系统的稳定性,通过仿真实例证明了所提控制算法的有效性及系统的稳定性。该方法能够在化工、冶金、机械等具有时滞特性的工业生产过程中得到很好的应用。     

A distribution-free newsvendor model with balking and lost sales penalty

In this paper, we extend the classical single period newsvendor model in an environment of customer balking, which occurs when customers are reluctant to buy a product if its available inventory falls below a threshold level. Since failure to make a sale usually results in a cost penalty, in addition to the opportunity cost of lost sales, we incorporate such costs in our model. Furthermore, we extend our model to include fixed ordering costs. Our analysis is based on the assumption that only the mean and the variance of the distribution of demand are known, without assuming any specific distributional form. We illustrate the concepts developed here through simple numerical examples and demonstrate the effectiveness of our approach by solving a set of 1000 randomly generated test problems.     

Development of the conceptual model of energy and utility management in textile processing: A soft systems approach

This paper aims to use soft systems methodology (SSM) to identify management support system opportunities for managing energy and utility usage in textile manufacturing processes. It presents an approach based on SSM to analyze the complex situation of developing an effective energy and utility management support system (EUMSS). This involves the identification of the scope of the system and user requirements, conceptual modeling of complex problem situations, identification of actors and decision processes, and information-needs modeling. The current study pioneers the examination of the application of SSM to the development of a novel EUMSS and contributes to the body of information systems knowledge in the context of EUMSS design. There appears to be limited academic research in the field of energy and utility system development and, in particular, in the area of EUMSS design, and none in the area of the application of SSM to EUMSS design. In addition, the modeling process could be beneficial if EUMSS design ideas could be widely shared and discussed. The identified scope and system requirements can serve as a guideline for designing and developing an effective EUMSS for textile processing.     

A solution business model: Capabilities and management practices for integrated solutions

The developed solution business model framework assists firms wishing to design solution business models by categorizing capabilities and management practices necessary for the effective management of such a business model. The developed framework integrates findings from a wide variety of research streams with the empirical data collected in an abductive research process, involving ten firms with multi-national operations. The framework consist of a solution process with four phases (develop solutions, create demand, sell solution, and deliver solution) and three groups of cross-functionality issues (commercialization, industrialization, and solution platform). The framework identifies twelve capability categories, and sixty-four capabilities and management practices pertinent to the effective management of solution business. The research points to the importance of cross-functional alignment within firms. An effective solution business model requires the intricate coordination of resources and business processes across all functions.     

Linking agricultural policies with obesity and noncommunicable diseases: A new perspective for a globalising world

In light of the shift in policy paradigm in agriculture from state intervention to market liberalisation and globalisation, this paper develops a series of hypotheses on the relationship between agricultural policies and consumer diets. The first hypothesis is that the paradigm shift has led to greater specialisation of production, so changing the ability and incentive for producers to supply certain foods relative to others. Second, the shift has affected farmgate prices (both up and down), so creating opportunities for the industries which purchase farm commodities (the food consuming industries – FCIs) to substitute lower priced ingredients, thereby influencing the nutritional quality and content of foods available in the marketplace. Third, it has increased the ability of the FCIs to “add value” through product innovation and marketing, creating a market characterised by highly differentiated products targeted to individualised preferences, thus increasing the acceptability of a wider variety and quantity of food products.