SPC—making it work for the gas transportation business

Transco is the main provider of gas transportation to domestic and commercial customers in mainland Britain. Gas arrives in Britain at a steady rate but is consumed with a distinct diurnal pattern. The safe and timely movement of gas from arrival at the beach in various places in Britain to delivery at burners is the main driver for System Operations. The movement of gas is meticulously controlled and monitored resulting in a mass of information on pressure, flow and temperature. Gas is stored temporarily in various storage vessels and is moved around the pipes and in and out of storage as demand dictates. Demand is mostly dictated by the weather and is therefore subject to much variation. Transco and its predecessors have been transporting gas for over 50 years and are very successful as judged by their excellent safety record and the continual delivery of gas. Nevertheless, the company wished to improve itself and make further use of the many measurements collected. SPC is ideal for improving communication and understanding through increased visibility of data. All companies have special issues to face when they implement SPC, and this paper describes the way these were dealt with in System Operations and the lessons learnt along the way. The first part describes how performance measures were chosen for investigation. It includes a novel use of correlation between output and day-to-day conditions, which was successfully turned into a measure to check the uncheckable. The second part is about the issues involved with early application of SPC when features of the system are still unexplained. SPC has helped enhance understanding of the complex transportation process, encouraged team work, improved performance and provided an objective means of decision making.     

SPC—a team effort for process improvement across four Area Control Centres

This paper describes an innovative application of statistical process control to the online remote control of the UK's gas transportation networks. The gas industry went through a number of changes in ownership, regulation, access to networks, organization and management culture in the 1990s. The application of SPC was motivated by these changes along with the desire to apply the best industrial statistics theory to practical problems. The work was initiated by a studentship, with the technology gradually being transferred to the industry. The combined efforts of control engineers and statisticians helped develop a novel SPC system. Having set up the control limits, a system was devised to automatically update and publish the control charts on a daily basis. The charts and an associated discussion forum are available to both managers and control engineers throughout the country at their desktop PCs. The paper describes methods of involving people to design first-class systems to achieve continual process improvement. It describes how the traditional benefits of SPC can be realized in a 'distal team working', and 'soft systems', context of four Area Control Centres, controlling a system delivering two thirds of the UK's energy needs.     

SPC—a team effort for process improvement across four Area Control Centres

This paper describes an innovative application of statistical process control to the online remote control of the UK's gas transportation networks. The gas industry went through a number of changes in ownership, regulation, access to networks, organization and management culture in the 1990s. The application of SPC was motivated by these changes along with the desire to apply the best industrial statistics theory to practical problems. The work was initiated by a studentship, with the technology gradually being transferred to the industry. The combined efforts of control engineers and statisticians helped develop a novel SPC system. Having set up the control limits, a system was devised to automatically update and publish the control charts on a daily basis. The charts and an associated discussion forum are available to both managers and control engineers throughout the country at their desktop PCs. The paper describes methods of involving people to design first-class systems to achieve continual process improvement. It describes how the traditional benefits of SPC can be realized in a 'distal team working', and 'soft systems', context of four Area Control Centres, controlling a system delivering two thirds of the UK's energy needs.     

Multidimensional scaling used in multivariate statistical process control

This paper considers the use of multidimensional scaling techniques in multivariate statistical process control. Principal components analysis, multiple principal components analysis, partial least squares and PARAFAC models have already been established as useful methods for such, but it should be possible to widen the portfolio of techniques to include others that come under the multidimensional scaling class. Some of these are briefly described-namely classical scaling, non-metric scaling, biplots, Procrustes analysis-and are then used on some gas transportation data provided by Transco.     

Multidimensional scaling used in multivariate statistical process control

This paper considers the use of multidimensional scaling techniques in multivariate statistical process control. Principal components analysis, multiple principal components analysis, partial least squares and PARAFAC models have already been established as useful methods for such, but it should be possible to widen the portfolio of techniques to include others that come under the multidimensional scaling class. Some of these are briefly described-namely classical scaling, non-metric scaling, biplots, Procrustes analysis-and are then used on some gas transportation data provided by Transco.     

SPC as a tool for creating a successful business measurement framework

Many companies are trying to get to the bottom of what their main objectives are and what their business should be doing. The new Six Sigma approach concentrates on clarifying business strategy and making sure that everything relates to company objectives. It is vital to clarify each part of the business in such a way that everyone can understand the causes of variation that can lead to improvements in processes and performance. This paper describes a situation where the full implementation of SPC methodology has made possible a visual and widely appreciated summary of the performance of one important aspect of the business. The major part of the work was identifying the core objectives and deciding how to encapsulate each of them in one or more suitable measurements. The next step was to review the practicalities of obtaining the measurements and their reliability and representativeness. Finally, the measurements were presented in chart form and the more traditional steps of SPC analysis were commenced. Data from fast changing business environments are prone to many different problems, such as the short previous span of typical data, strange distributions and other uncertainties. Issues surrounding these and the eventual extraction of a meaningful set of information will be discussed in the paper. The measurement framework has proved very useful and, from an initial circulation of a handful of people, it now forms an important part of an information process that provides responsible managers with valuable control information. The measurement framework is kept fresh and vital by constant review and modifications. Improved electronic data collection and dissemination of the report has proved very important.     

SPC as a tool for creating a successful business measurement framework

Many companies are trying to get to the bottom of what their main objectives are and what their business should be doing. The new Six Sigma approach concentrates on clarifying business strategy and making sure that everything relates to company objectives. It is vital to clarify each part of the business in such a way that everyone can understand the causes of variation that can lead to improvements in processes and performance. This paper describes a situation where the full implementation of SPC methodology has made possible a visual and widely appreciated summary of the performance of one important aspect of the business. The major part of the work was identifying the core objectives and deciding how to encapsulate each of them in one or more suitable measurements. The next step was to review the practicalities of obtaining the measurements and their reliability and representativeness. Finally, the measurements were presented in chart form and the more traditional steps of SPC analysis were commenced. Data from fast changing business environments are prone to many different problems, such as the short previous span of typical data, strange distributions and other uncertainties. Issues surrounding these and the eventual extraction of a meaningful set of information will be discussed in the paper. The measurement framework has proved very useful and, from an initial circulation of a handful of people, it now forms an important part of an information process that provides responsible managers with valuable control information. The measurement framework is kept fresh and vital by constant review and modifications. Improved electronic data collection and dissemination of the report has proved very important.     

Climbing the Electronic Capitol Hill: Personal and Professional Reflections on Teaching about Congress

The Information Revolution, particularly evidenced by the Internet, e-mail and online access to government documents, has significantly affected the way Congress conducts business. The author reflects on the changes that he has had to make during his seven years of teaching a course on Congressional Office Operations for the U.S. Department of Agriculture (USDA) Graduate School. Through personal experiences, interviews, and historical perspectives, he describes changes in information resources, constituent communications, and press operations on Capitol Hill and how these changes have affected course content. He also describes how the events of September 11, 2001, and the anthrax mail problem have forced consideration of an electronic Congress. Serials Review 2002; 28:287–294.     

物流统计初探

一、物流统计调查的必要性物流包括运输、仓储、包装、装卸搬运、流通加工、配送、信息等职能 ,社会经济运行中生产、流通、消费等环节均涉及到物流。随着经济全球化、一体化的发展和现代科学技术、管理技术在物流行业的应用 ,使原来分散于不同经济领域和环节的相对独立的物流功能发生了密切的联系 ,统一为综合物流系统 ,这不仅提高了物流本身的运作效率 ,而且更好地适应了市场上用户对物流的要求 ,使物流业发展成为有别与传统运输、仓储行业的新兴产业。现代物流业一般由交通运输、储运、货代、流通加工和配送等行业构成。交通运输行业包括…     

Climbing the Electronic Capitol Hill

Abstract

The Information Revolution, particularly evidenced by the Internet, e-mail and online access to government documents, has significantly affected the way Congress conducts business. The author reflects on the changes that he has had to make during his seven years of teaching a course on Congressional Office Operations for the U.S. Department of Agriculture (USDA) Graduate School. Through personal experiences, interviews, and historical perspectives, he describes changes in information resources, constituent communications, and press operations on Capitol Hill and how these changes have affected course content. He also describes how the events of September 11, 2001, and the anthrax mail problem have forced consideration of an electronic Congress. Serials Review 2002; 28:287–294.     

Robust design of adaptive control charts for manual manufacturing/inspection workstations

Often the manufacturing and the inspection workstations in a manufacturing process can coincide: thus, in these workstations the statistical process control (SPC) procedure of collecting sample statistics related to a critical-to-quality parameter is a task required to be done by the same worker who has to complete the working operations on a part. The aim of this study is to design a local SPC inspection procedure implementing an adaptive Shewhart control chart locally managed by the worker within the manufacturing workstation: the economic design of the inspection procedure is constrained by the expected number of false alarms issued and is restricted to those designs feasible with respect to the available shared labour resource. Furthermore, a robust approach that models the shift of the controlled parameter mean as a random variable is taken into account. The numerical analysis allows the most influencing environmental process factors to be captured and commented upon. The obtained results show that a few process operating parameters drive the choice of performing a robust optimization and the selection of the optimal SPC adaptive procedure.     

中国道路运输能力影响因素分析

运输业是国民经济的基础产业,其对国民经济的贡献不仅在于运输业创造的直接价值,也在于其对国民经济其他方面的影响。因此,对道路运输能力的研究是一个国家经济研究体系中必不可少的部分。本文使用结构方程模型对影响我国道路运输能力的分析,得到各影响因素及其作用大小,为该领域的进一步量化研究做出了铺垫。     

Statistical issues in the prospective monitoring of health outcomes across multiple units

Summary.  Following several recent inquiries in the UK into medical malpractice and failures to deliver appropriate standards of health care, there is pressure to introduce formal monitoring of performance outcomes routinely throughout the National Health Service. Statistical process control (SPC) charts have been widely used to monitor medical outcomes in a variety of contexts and have been specifically advocated for use in clinical governance. However, previous applications of SPC charts in medical monitoring have focused on surveillance of a single process over time. We consider some of the methodological and practical aspects that surround the routine surveillance of health outcomes and, in particular, we focus on two important methodological issues that arise when attempting to extend SPC charts to monitor outcomes at more than one unit simultaneously (where a unit could be, for example, a surgeon, general practitioner or hospital): the need to acknowledge the inevitable between-unit variation in 'acceptable' performance outcomes due to the net effect of many small unmeasured sources of variation (e.g. unmeasured case mix and data errors) and the problem of multiple testing over units as well as time. We address the former by using quasi-likelihood estimates of overdispersion, and the latter by using recently developed methods based on estimation of false discovery rates. We present an application of our approach to annual monitoring 'all-cause' mortality data between 1995 and 2000 from 169 National Health Service hospital trusts in England and Wales.     

One-Class Classification-Based Control Charts for Monitoring Autocorrelated Multivariate Processes

In recent years, statistical process control (SPC) of multivariate and autocorrelated processes has received a great deal of attention. Modern manufacturing/service systems with more advanced technology and higher production rates can generate complex processes in which consecutive observations are dependent and each variable is correlated. These processes obviously violate the assumption of the independence of each observation that underlies traditional SPC and thus deteriorate the performance of its traditional tools. The popular way to address this issue is to monitor the residuals—the difference between the actual value and the fitted value—with the traditional SPC approach. However, this residuals-based approach requires two steps: (1) finding the residuals; and (2) monitoring the process. Also, an accurate prediction model is necessary to obtain the uncorrelated residuals. Furthermore, these residuals are not the original values of the observations and consequently may have lost some useful information about the targeted process. The main purpose of this article is to examine the feasibility of using one-class classification-based control charts to handle multivariate and autocorrelated processes. The article uses simulated data to present an analysis and comparison of one-class classification-based control charts and the traditional Hotelling's T ² chart.     

社会核算矩阵与国民经济账户、投入产出表的关系研究

社会核算矩阵(SAM)刻画了社会经济主体间通过要素市场、商品市场而发生的交易和收支转移活动。结合国民经济核算理论研究了国民经济账户、投入产出(IO)表与SAM之间的关系,结果表明:SAM是以矩阵形式表示的国民经济核算体系(SNA)账户,SAM以复式记账的核算原则和矩阵的形式提供了国民经济的另外一种核算方式;IO表是编制SAM的重要数据来源。     

E-serial Titles That Disappear

Abstract

CONSER (Cooperative Online Serials Program) members are currently dealing with the problem of how to catalog electronic journals that over time do not retain their titles on earlier issues. The dilemma for catalogers is whether to use the successive entry rules of AACR2 (Anglo-American Cataloging Rules) for serials or to apply the latest entry approach used for integrating resources. CONSER members are currently working on a discussion paper that will weigh the pros and cons of successive and latest entry to be presented at the CONSER Operations Committee meeting in May 2002. Discussion of the issues will provide the background for a Library of Congress Rule Interpretation. Serials Review 2002; 28:222–224.     

Cross-national comparison of internal migration: issues and measures

Summary. Our objectives are to identify the issues that researchers encounter when measuring internal migration in different countries and to propose key indicators that analysts can use to compare internal migration at the 'national' level. We establish the benefits to be gained by a rigorous approach to cross-national comparisons of internal migration and discuss issues that affect such comparisons. We then distinguish four dimensions of internal migration on which countries can be compared and, for each dimension, identify a series of summary measures. We illustrate the issues and measures proposed by comparing migration in Australia and Great Britain.     

Forecasting the Incidence of Cancer in Regional Victoria,Australia

Loddon Mallee Integrated Cancer Service plays a key role in planning the delivery of cancer services in the Loddon Mallee Region of Victoria, Australia. Forecasting the incidence of cancer is an important part of planning for these services. This article is written from an industry perspective. We describe the context of our work, review the literature on forecasting the incidence of cancer, discuss contemporary approaches, describe our experience with forecasting models, and list issues associated with applying these models. An extensive bibliography illustrates the world-wide interest in this forecasting problem. We hope that it is useful to researchers.     

On the Run Length of a State-Space Control Chart for Multivariate Autocorrelated Data

The literature on statistical process control (SPC) describes the negative effects of autocorrelation in terms of the increase in false alarms. This has been treated by the individual modeling of each series or the application of VAR models. In the former case, the analysis of the cross correlation structure between the variables is altered. In the latter, if the cross correlation is not strong, the filtering process may modify the weakest relations. In order to improve these aspects, state-space models have been introduced in multivariate statistical process control (MSPC). This article presents a proposal for building a control chart for innovations, estimating its average run length to highlight its advantages over the VAR approach mentioned above.     

Cofactors and markers of disease progression in human immunodeficiency virus infection

The identification of factors which are related to human immunodeficiency virus (HIV) disease progression, either by a direct interaction with HIV to increase the rate of disease progression or by providing an indication of an infected individual's likely prognosis, can have great value when understanding HIV pathogenesis and in the development of novel therapeutic approaches. This paper describes the roles of the CD4 cell count and the viral load as markers of disease progression and discusses the recent findings on chemokine receptors in HIV infection. Our current knowledge on these factors is summarized and unresolved statistical issues are highlighted.