The maintenance implications of the customization of ERP software

Enterprise resource planning (ERP) software is a dominant approach for dealing with legacy information system problems. In order to avoid invalidating maintenance and development support from the ERP vendor, most organizations reengineer their business processes in line with those implicit within the software. Regardless, some customization is typically required. This paper presents two case studies of ERP projects where customizations have been performed. The case analysis suggests that while customizations can give true organizational benefits, careful consideration is required to determine whether a customization is viable given its potential impact upon future maintenance. Copyright © 2001 John Wiley & Sons, Ltd.

F. + H. Engel AG: Erfolg mit releasefähiger Standard-Software

Die Firma F. + H. Engel AG ist ein Bieler Familienunternehmen, das an fünf Standorten tätig ist und die Geschäftsbereiche Stahl, Haustechnik und Eisenwaren abdeckt. Seit über 15 Jahren setzt ENGEL für die Unterstützung ihrer Handelsprozesse die Standardsoftware OpaccOne ein. Dabei orientiert sich das Unternehmen an den durch die Software gegebenen Möglichkeiten, um eine möglichst sichere, stabile und langfristig tragfähige Lösung sicher zu stellen. Dank der Releasefähigkeit der gewählten Standard-Business-Software profitierte Engel ohne grössere Umstellungen von deren laufend erweiterten Fähigkeiten in Bezug auf Funktionalität, Technologie, Anpassungs- und Erweiterungsmöglichkeiten. Dadurch konnte sich ENGEL über die Jahre mit dieser Software stetig weiterentwickeln und auch neue Anforderungen abdecken. Problematisch erwies sich die durch die Einführung eines Webshops deutlich höhere Anforderung an Umfang und Qualität der Produktstammdaten für das umfangreiche Sortiment. Der Aufwand für deren Pflege konnte von ENGEL auf die Dauer nicht geleistet werden. Deshalb entschied man sich für eine zweigleisige Strategie, indem für einen Teil des Sortiments auf die Dienstleistungen eines externen Inhaltsanbieters zurückgegriffen wird

Beyond enterprise resource planning projects : Innovative strategies for competitive advantage

ABSTRACT A rapidly changing business environment and legacy IT problems has resulted in many organisations implementing standard package solutions. This 'common systems' approach establishes a common IT and business process infrastructure within organisations and its increasing dominance raises several important strategic issues. These are to what extent do common systems impose common business processes and management systems on competing firms, and what is the source of competitive advantage if the majority of firms employ almost identical information systems and business processes? A theoretical framework based on research into legacy systems and earlier IT strategy literature is used to analyse three case studies in the manufacturing, chemical and IT industries. It is shown that the organisations are treating common systems as the core of their organisations' abilities to manage business transactions. To achieve competitive advantage they are clothing these common systems with information systems designed to capture information about competitors, customers and suppliers, and to provide a basis for sharing knowledge within the organisation and ultimately with economic partners. The importance of these approaches to other organisations and industries is analysed and an attempt is made at outlining the strategic options open to firms beyond the implementation of common business systems.

Best of breed IT strategy: an alternative to enterprise resource planning systems

Abstract - Enterprise Resource Planning (ERP) software has become the dominant strategic platform for supporting enterprise-wide business processes. However, single vendor ERP software systems have been criticised for not meeting specific organisation and industry requirements. An alternative approach ‘Best of Breed (BoB)’, integrates components of software from multiple standard package vendors, and in some cases custom components. The objective is to develop enterprise systems that are more closely aligned with the requirements of an organisation. Although this approach may not be common at present it is likely to grow in importance due to business needs and technology advances such as the componentisation of ERP software. A case study analysis of a BoB implementation at a global entertainment's company is used as a platform for the discussion of the issues associated with this strategy and a comparison is made with the single vendor ERP alternative. The analysis centres on the complexity of implementation, the differences in the levels of functionality and business fit and the maintenance requirements.

ERP and best of breed : a comparative analysis

Enterprise Resource Planning (ERP) software is the dominant strategic platform for supporting enterprise-wide business processes. However, it has been criticised for being inflexible and not meeting specific organisation and industry requirements. An alternative, Best of Breed (BoB), integrates components of standard package and/or custom software. The objective is to develop enterprise systems that are more closely aligned with the business processes of an organisation. A case study of a BoB implementation facilitates a comparative analysis of the issues associated with this strategy and the single vendor ERP alternative. The paper illustrates the differences in complexity of implementation, levels of functionality, business process alignment potential and associated maintenance.

Spatially explicit structural equation modeling

Structural equation modeling (SEM) is a powerful statistical approach for the testing of networks of direct and indirect theoretical causal relationships in complex data sets with intercorrelated dependent and independent variables. SEM is commonly applied in ecology, but the spatial information commonly found in ecological data remains difficult to model in a SEM framework. Here we propose a simple method for spatially explicit SEM (SE-SEM) based on the analysis of variance/covariance matrices calculated across a range of lag distances. This method provides readily interpretable plots of the change in path coefficients across scale and can be implemented using any standard SEM software package. We demonstrate the application of this method using three studies examining the relationships between environmental factors, plant community structure, nitrogen fixation, and plant competition. By design, these data sets had a spatial component, but were previously analyzed using standard SEM models. Using these data sets, we demonstrate the application of SE-SEM to regularly spaced, irregularly spaced, and ad hoc spatial sampling designs and discuss the increased inferential capability of this approach compared with standard SEM. We provide an R package, sesem, to easily implement spatial structural equation modeling.

Variability of marine climate on the North Icelandic Shelf in a 1357-year proxy archive based on growth increments in the bivalve Arctica islandica

A multicentennial and absolutely-dated shell-based chronology for the marine environment of the North Icelandic Shelf has been constructed using annual growth increments in the shell of the long-lived bivalve clam Arctica islandica. The region from which the shells were collected is close to the North Atlantic Polar Front and is highly sensitive to the varying influences of Atlantic and Arctic water masses. A strong common environmental signal is apparent in the increment widths, and although the correlations between the growth increment indices and regional sea surface temperatures are significant at the 95% confidence level, they are low (r ~ 0.2), indicating that a more complex combination of environmental forcings is driving growth. Remarkable longevities of individual animals are apparent in the increment-width series used in the chronology, with several animals having lifetimes in excess of 300 years and one, at 507 years, being the longest-lived non-colonial animal so far reported whose age at death can be accurately determined. The sample depth is at least three shells after AD 1175, and the time series has been extended back to AD 649 with a sample depth of one or two by the addition of two further series, thus providing a 1357-year archive of dated shell material. The statistical and spectral characteristics of the chronology are investigated by using two different methods of removing the age-related trend in shell growth. Comparison with other proxy archives from the same region reveals several similarities in variability on multidecadal timescales, particularly during the period surrounding the transition from the Medieval Climate Anomaly to the Little Ice Age.

Design of a Multibus-compatible colour graphics subsystem

Colour graphics subsystems can be used in a variety of applications such as high-end business graphics, low-end scientific computations, and for realtime display of process control diagrams. The design of such a subsystem is shown. This subsystem can be added to any Multibus-compatible microcomputer system. The use of an NEC 7220 graphics display controller chip has simplified the design to a considerable extent. CGRAM (CORE graphics on Multibus), a comprehensive subset of the CORE graphics standard package, is supported on the subsystem.

污水生化处理过程仿真及在A~2/O工艺改进中的应用

基于国际水协会IWA发布的国际评价基准Benchmark,建立了与污水处理厂实际特性相近的标准仿真平台。对污水处理传统A2/O工艺做了合理改进,在不影响出水水质的情况下,取消内回流。应用该平台分别对晴天、雨天与暴雨三种天气的工艺过程模拟,验证了工艺改进的合理性。仿真结果表明,与传统A2/O工艺相比,出水指标差别不大,但污泥泵能耗降低约50%。

Using interviewer random effects to remove selection bias from HIV prevalence estimates

Background: Selection bias in HIV prevalence estimates occurs if non-participation in testing is correlated with HIV status. Longitudinal data suggests that individuals who know or suspect they are HIV positive are less likely to participate in testing in HIV surveys, in which case methods to correct for missing data which are based on imputation and observed characteristics will produce biased results. Methods: The identity of the HIV survey interviewer is typically associated with HIV testing participation, but is unlikely to be correlated with HIV status. Interviewer identity can thus be used as a selection variable allowing estimation of Heckman-type selection models. These models produce asymptotically unbiased HIV prevalence estimates, even when non-participation is correlated with unobserved characteristics, such as knowledge of HIV status. We introduce a new random effects method to these selection models which overcomes non-convergence caused by collinearity, small sample bias, and incorrect inference in existing approaches. Our method is easy to implement in standard statistical software, and allows the construction of bootstrapped standard errors which adjust for the fact that the relationship between testing and HIV status is uncertain and needs to be estimated. Results: Using nationally representative data from the Demographic and Health Surveys, we illustrate our approach with new point estimates and confidence intervals (CI) for HIV prevalence among men in Ghana (2003) and Zambia (2007). In Ghana, we find little evidence of selection bias as our selection model gives an HIV prevalence estimate of 1.4% (95% CI 1.2% – 1.6%), compared to 1.6% among those with a valid HIV test. In Zambia, our selection model gives an HIV prevalence estimate of 16.3% (95% CI 11.0% - 18.4%), compared to 12.1% among those with a valid HIV test. Therefore, those who decline to test in Zambia are found to be more likely to be HIV positive. Conclusions: Our approach corrects for selection bias in HIV prevalence estimates, is possible to implement even when HIV prevalence or non-participation is very high or very low, and provides a practical solution to account for both sampling and parameter uncertainty in the estimation of confidence intervals. The wide confidence intervals estimated in an example with high HIV prevalence indicate that it is difficult to correct statistically for the bias that may occur when a large proportion of people refuse to test.

Estimating numbers of infectious units from serial dilution assays

The paper concerns the design and analysis of serial dilution assays to estimate the infectivity of a sample of tissue when it is assumed that the sample contains a finite number of indivisible infectious units such that a subsample will be infectious if it contains one or more of these units. The aim of the study is to estimate the number of infectious units in the original sample. The standard approach to the analysis of data from such a study is based on the assumption of independence of aliquots both at the same dilution level and at different dilution levels, so that the numbers of infectious units in the aliquots follow independent Poisson distributions. An alternative approach is based on calculation of the expected value of the total number of samples tested that are not infectious. We derive the likelihood for the data on the basis of the discrete number of infectious units, enabling calculation of the maximum likelihood estimate and likelihood-based confidence intervals. We use the exact probabilities that are obtained to compare the maximum likelihood estimate with those given by the other methods in terms of bias and standard error and to compare the coverage of the confidence intervals. We show that the methods have very similar properties and conclude that for practical use the method that is based on the Poisson assumption is to be recommended, since it can be implemented by using standard statistical software. Finally we consider the design of serial dilution assays, concluding that it is important that neither the dilution factor nor the number of samples that remain untested should be too large.

Active-control trials with binary data: a comparison of methods for testing superiority or non-inferiority using the odds ratio

This paper considers methods for testing for superiority or non-inferiority in active-control trials with binary data, when the relative treatment effect is expressed as an odds ratio. Three asymptotic tests for the log-odds ratio based on the unconditional binary likelihood are presented, namely the likelihood ratio, Wald and score tests. All three tests can be implemented straightforwardly in standard statistical software packages, as can the corresponding confidence intervals. Simulations indicate that the three alternatives are similar in terms of the Type I error, with values close to the nominal level. However, when the non-inferiority margin becomes large, the score test slightly exceeds the nominal level. In general, the highest power is obtained from the score test, although all three tests are similar and the observed differences in power are not of practical importance. Copyright (C) 2007 John Wiley & Sons, Ltd.