Combinatorial Equivalence of Fractional Factorial Designs

Two symmetrical fractional factorial designs are said to be combinatorially equivalent if one design can be obtained from another by reordering the runs, relabeling the factors and relabeling the levels of one or more factors. This article presents concepts of ordered distance frequency matrix, distance frequency vector, and reduced distance frequency vector for a design. Necessary conditions for two designs to be combinatorial equivalent based on these concepts are presented. A new algorithm based on the results obtained is proposed to check combinatorial non-equivalence of two factorial designs and several illustrating examples are provided.     

The Difficult History of Ancillary Units: The Obstacles and Potential Opportunities to Increase the Heterogeneity of Neighborhoods and the Flexibility of Households in the United States

ABSTRACT

Most aging Americans express the desire to stay in their current home for the rest of their lives. However, as literature and practice indicate, aging in place cannot be successfully achieved in all places, especially in those places where zoning regulations and building codes act as barriers to the flexible adaptation of environments. One possible solution could come from the legalization of what is commonly known as granny flats, or more technically as Ancillary Dwelling Units. This article is divided into three parts. The first part is a brief history of Ancillary Dwelling Units. The second part focuses on the critical role played by local and state urban planning policies in the future of Ancillary Dwelling Units. California is used as a noteworthy example. The third part discusses how positive outcomes for senior residents who have Ancillary Dwelling Units legally present in their neighborhoods are linked to the appropriateness of their design.     

The General Segmented Distribution

We develop a distribution supported on a bounded interval with a probability density function that is constructed from any finite number of linear segments. With an increasing number of segments, the distribution can approach any continuous density function of arbitrary form. The flexibility of the distribution makes it a useful tool for various modeling purposes. We further demonstrate that it is capable of fitting data with considerable precision—outperforming distributions recommended by previous studies. We suggest that this distribution is particularly effective in fitting data with sufficient observations that are skewed and multimodal.     

A Design of Attributes Double Sampling Plans for Three-class Products

In this article, a new attributes double sampling plan for three-class products (ADSPTP) is presented, and the corresponding operating characteristic function is constructed based on the given procedure of performing ADSPTP. Average sample numbers (ASN) for complete inspection and curtailed inspection of the second sample are derived and the extreme point is discussed on the three-dimensional ASN surface. In addition, the differences arising from different parameters are studied. Sampling plans are designed by a nonlinear optimization model. Finally, numerical examples and discussions are given to illustrate the obtained results, and tables of the designed plans under various conditions are provided.     

INFORMATION-CENTRED DESIGN: A methodology for designing virtual meeting DESIGN environments

Development of single-user computer applications has often been based on user-centred or task-centred design methodologies, with some success. These methodologies are also useful for guiding the development of multi-user CSCW applications whenever the basic characteristics of the users, or the type of tasks for which the system is being designed are identifiable. The effectiveness of these methodologies as a basis for the design of virtual meeting environments for supporting community-based activities, on the other hand, is rather limited. This is mainly due to the fact that for such systems it is not generally possible to identify the user or task requirements, as these vary considerably from one community to another, or even within the same community over a period of time. New methodologies need to be devised, or existing methodologies have to be modified, to direct the development of virtual environments for which the characteristics of the users or their activities are not known in advance. This paper introduces the concept of information-centred design. Information-centred design, though not fully devised yet, focuses on the identification of the type of information, as well as the way it is collected and utilized by the users of a virtual meeting environment. This pool of information, which plays an important role in facilitating interaction and communication between the members of a community, could be defined as their communal memory.     

Redesigning a Cellular Manufacturing System to Handle Long-Term Demand Changes: A Methodology and Investigation*

Cellular manufacturing systems have been proposed as an alternative to the job shop since they provide some of the operational benefits of a flow line production process, while retaining to some extent the flexibility of job shops. However, this must be balanced against the possibility of additional initial investments in equipment to form the cells and a certain loss in manufacturing flexibility, particularly in terms of the ability to deal with long-term demand changes. This paper presents a model-based heuristic cell system redesign methodology to deal with such demand changes. The methodology is validated and applied to system designs generated from several data sets published in the literature. Results show that different kinds of demand changes incur distinct kinds of costs. Further, characteristics of cell designs that can handle long-term demand changes at least cost are identified.     

民营中小企业信用担保体系研究

民营中小企业信用担保体系可归纳出四大设计原理：功能原理、经营原理、正选原理和博弈原理。针对信用担保体系的问题，提出其健全与发展的建议是：清晰定位担保对象；科学择优担保运作方式：完善资金补偿机制；健全风险分散机制；正确发挥政府作用；促进社会信用体系建设；加强监管体系；建立社会化中介服务体系；加强金保合作，形成共生机制。     

A Mixed Model-assisted Regression Estimator that Uses Variables Employed at the Design Stage

The Generalized regression estimator (GREG) of a finite population mean or total has been shown to be asymptotically optimal when the working linear regression model upon which it is based includes variables related to the sampling design. In this paper a regression estimator assisted by a linear mixed superpopulation model is proposed. It accounts for the extra information coming from the design in the random component of the model and saves degrees of freedom in finite sample estimation. This procedure combines the larger asymptotic efficiency of the optimal estimator and the greater finite sample stability of the GREG. Design based properties of the proposed estimator are discussed and a small simulation study is conducted to explore its finite sample performance.     

Construction of Youden hyperrectangles

Youden hyperrectangles are higher-dimensional generalizations of balanced block designs and generalized Youden designs. This kind of design has been shown to be optimal for the elimination of multi-way heterogeneity. In this paper, patchwork and geometric methods are combined to construct Youden hyperrectangles for many parameter values.