关于电热水器模糊PID水温控制系统的设计

普通电热水器都是采用手动方式改变冷、热进水阀的旋转角度来调节水温的,而温度是一个非线性、大时变和大滞后的被控对象,在调节进水阀的过程中有时很难把握控制力度,这样很容易造成水电资源浪费,而且在使用时也带来很多不便.本文设计了一种采用模糊PID控制算法的恒温控制系统,对冷、热出水阀旋转角度实行自动调节,实现了普通电热水器出水温度的高精度恒温控制.     

A technical note on “A fuzzy set approach for R&D portfolio selection using a real options valuation model” by Wang and Hwang (2007)

In this paper, three critical issues with the paper “A fuzzy set approach for R&D portfolio selection using a real options valuation model”, coauthored by Wang and Hwang and published in Omega 2007 are addressed. Shortcomings of the original work are highlighted and corrective measures to improve the approach are proposed.     

Disentangling combinations and contingencies of generic strategies: A set-theoretic configurational approach

Porter's framework of generic strategies conceptualizes key elements of firms' strategic positions in their industry. Research on these generic strategies has been challenged by the complexity of capturing relations between generic strategies (i.e., cost leadership, differentiation, and focus) and their interdependencies with other strategic commitments for performance outcomes. We address these challenges by utilizing fuzzy set Qualitative Comparative Analysis (fsQCA) to explore the causal complexity underlying the links between generic strategies and firm performance. Specifically, we study combinations of firms' generic strategies and other strategy attributes as paths to high or low performance in the U.S. and Canadian airline industry. We find six equifinal configurations that are consistently linked to high performance and nine configurations that are consistently linked to the absence of high performance. Our findings shed light on the contingencies underlying performance consequences of generic strategies. Consequently they redirect theoretical debates on the links between generic strategies and firm performance as well as on the superiority of pure versus hybrid generic strategies towards relations of set-theoretic of necessity and sufficiency. Specifically, we show that having a generic strategy advantage is not sufficient for high performance but that it is a vital ingredient in recipes for success. Similarly, our findings suggest that a generic strategy disadvantage is not sufficient for low performance, but is a key ingredient in all paths to poor performance. We conclude with a discussion of our study's contributions to the literature, suggestions for future research, and implications for managerial practice.     

A case study on the suitability of STARS for green campus in China

With the continuous development of China's green campus, its future construction should learn from foreign advanced development experience and achievements. On the one hand, STARS, a global advanced green campus evaluation system, should be introduced to China's green campus construction and on the other hand, the suitability for China's actual needs should also be considered. Therefore, this study mainly studies the suitability of STARS indicators for green campus in China. Taking a representative university of green campus in China as a specific case, starting from the demand side, this paper uses the fuzzy comprehensive evaluation method to evaluate the users’ satisfaction of green campus construction. Comparing the result of satisfaction assessment with the result of STARS’s sustainable evaluation, the STARS’s indexes are divided into four regional grades by two-dimensional suitability evaluation coordinate system. The results show that STARS is generally suitable for green campus evaluation in China, but two of the evaluation categories need to modify the evaluation scores and weights; the other two categories are not suitable and need to be removed or changed. The purpose is to provide suggestions for the optimization of the evaluation of green campus in China.     

A hybrid mathematical programming model for optimal project portfolio selection using fuzzy inference system and analytic hierarchy process

The primary goal in project portfolio management is to select and manage the optimal set of projects that contribute the maximum in business value. However, selecting Information Technology (IT) projects is a difficult task due to the complexities and uncertainties inherent in the strategic-operational nature of the process, and the existence of both quantitative and qualitative criteria. We propose a two-stage process to select an optimal project portfolio with the aim of maximizing project benefits and minimizing project risks. We construct a two-stage hybrid mathematical programming model by integrating Fuzzy Analytic Hierarchy Process (FAHP) with Fuzzy Inference System (FIS). This hybrid framework provides the ability to consider both the quantitative and qualitative criteria while considering budget constraints and project risks. We also present a real-world case study in the cybersecurity industry to exhibit the applicability and demonstrate the efficacy of our proposed method.     

用改进田中法确定超静定杆系的价值分析对象

在田中法基础上采用模糊综合评判以确定等效用常数S的数值,提出了改进田中法。文中应用此法确定了超静定杆系结构的价值分析对象,并以实例说明应用。     

工作生活质量评价指数研究——基于模糊数量化Ⅲ类模型

工作生活质量是一个在企业人力资源管理中越来越受到重视的概念。文章运用模糊数量化Ⅲ类模型对工作生活质量指标体系进行处理,将定性指标转换为定量指标,构建工作生活质量评价指数,实现对人员工作生活质量定量、规范的测量和评价,并以中国各大地区40多家航空企业的1 276名科技人员样本为对象进行实证分析。研究结果表明,运用模糊数量化Ⅲ类模型能够有效构建工作生活质量评价指数并实现人员工作生活质量定量、规范的测量和评价。     

废旧家电逆向物流综合效益评价研究

目前,废旧家电回收处理已成为全球实现资源再利用的共性问题,建立废旧家电逆向物流体系迫在眉睫。选取经济效益、管理水平、社会效益3个方面的指标,运用层次分析法（AHP）、360度反馈法与模糊综合评价法（FCE）对废旧家电逆向物流的综合效益进行评价,构建起比较完整的废旧家电逆向物流评价模型,并通过算例验证该方法的有效性。     

A surprising property of uniformly best linear affine estimation in linear regression when prior information is fuzzy

It is already shown in Arnold and Stahlecker (2009) that, in linear regression, a uniformly best estimator exists in the class of all Γ-compatible$\Gamma \text{-compatible}$ linear affine estimators. Here, prior information is given by a fuzzy set Γ$\Gamma$ defined by its ellipsoidal α-cuts$\alpha \text{-cuts}$. Surprisingly, such a uniformly best linear affine estimator is uniformly best not only in the class of all Γ-compatible$\Gamma \text{-compatible}$ linear affine estimators but also in the class of all estimators satisfying a very weak and sensible condition. This property of a uniformly best linear affine estimator is shown in the present paper. Furthermore, two illustrative special cases are mentioned, where a generalized least squares estimator on the one hand and a general ridge or Kuks–Olman estimator on the other hand turn out to be uniformly best.     

基于数学模型的高校贫困生评定方法

本文针对现行的贫困生助学金分配政策不完善的情况,建立了两种数学模型得到贫困生评价体系。在选取了学生的贫困程度、节俭程度、学习情况和德育素质作为评价指标后,分别建立了基于模糊层次分析法的＂打分法＂和综合评价法两个模型,从定性和定量的角度得到了高校贫困生的评价体系。