Pitfalls in portfolio planning

This paper presents an analysis and comparison of the Boston Consulting Group, McKinsey & Co., and Arthur D. Little portfolio models and a discussion of the theoretical and operational problems with the general portfolio construct. The models seem to share the goal of optimizing the firm's financial performance and the same fundamental assumptions. The strategies suggested by each model will not always be the same because of differences in the structure of the three models. Also strategic analysis of each unit is necessary to avoid the pitfalls caused by the theoretical and operational problems with the portfolio construct.     

An augmented data scoring algorithm for maximum likelihood

The expectation-maximization (EM) method facilitates computation of max¬imum likelihood (ML) and maximum penalized likelihood (MPL) solutions. The procedure requires specification of unobservabie complete data which augment the measured or incomplete data. This specification defines a conditional expectation of the complete data log-likelihood function which is computed in the E-stcp. The EM algorithm is most effective when maximizing the iunction Q{0) denned in the F-stnp is easier than maximizing the likelihood function.

The Monte Carlo EM (MCEM) algorithm of Wei & Tanner (1990) was introduced for problems where computation of Q is difficult or intractable. However Monte Carlo can he computationally expensive, e.g. in signal processing applications involving large numbers of parameters. We provide another approach: a modification of thc standard EM algorithm avoiding computation of conditional expectations.     

Putting Localism in Place: Conservative Images of the Good Community and the Contradictions of Planning Reform in England

Over the past 5 years, the UK Coalition and subsequent Conservative governments have sought to develop an agenda of localism. Recent research has evaluated how this has played out in practice. This article takes a different approach, interpreting how the language of community and place in English politics has been mobilized in reforms of the country’s planning system. We do this by tracing how conservative traditions of political thought and imagery of place were used to advance localism. This reveals a range of contradictions within the English localism agenda and highlights the wider political challenges raised by attempts to mobilize the affective and morally charged language of the local.     

Against Structure: A Critique of Morphogenetic Social Theory

This article criticises the ontology of Margaret Archer's morphogenetic social theory, arguing that the concept of autonomous social structure on which she bases this social theory is contradictory. Against the ontological contradictions of Archer's work, the article tries to re-habilitate the interpretive tradition which Archer dismisses, showing that only this tradition provides a logically coherent and methodologically useful social ontology, which consists only of individuals and their social relations.     

Integration Between Business Planning and Information Systems Planning: Validating a Stage Hypothesis

This paper proposes and empirically validates a stages of growth model for the evolution of Information Systems Planning (ISP). A questionnaire survey of senior IS executives is used to gather information pertaining to the stages of growth model, which includes measurement of the nature and level of integration between business planning (BP) and ISP. The del test is used to validate empirically benchmark variables for each stage of BP-ISP integration. The results support the stages of growth model of BP-ISP integration and the benchmark variables are generally found to be successful in predicting the stage of integration.     

Media Appropriateness: Effects of Experience on Communication Media Choice

Organizations are faced with a myriad of emerging advanced information technologies. Management may be anxious about the numerous choices while simultaneously yearning for instant realization of benefits promised by the adopted technologies. Management should also be aware that the eventual institutional use of these technologies is dependent upon the learning and training opportunities presented to individuals. Individual approval or established perceptions toward technology appropriateness are mostly idiosyncratic and contingent upon numerous factors such as task goals or prior technology experience. This paper examines the effect of learning experiences with nine communication media, based on perception changes of media appropriateness. Two hundred and ninety-five MBA students participated in a longitudinal quasi-experimental study. Results indicate that traditionally rich media such as face-to-face, group meetings, and telephone were consistently perceived to be more appropriate than emerging new media over time. However, an individual's specific experience with communication media affects perceptions of media appropriateness, and this is particularly evident in computer-based communications. In addition, changes in perception of media appropriateness were directly related to the participants' learning experience and were particularly salient with new media. Furthermore, increased use of some media was found to be associated with decreased use of other media. This study demonstrates that deliberate technology-use mediation can be an effective management mechanism to facilitate an individual's ability to gain experience in the use of new technologies. This paper also suggests that an individual's media experiences and temporal factors are two important but underemphasized factors in understanding and studying technology choice and use.     

The potential value of mosses for stormwater management in urban environments

Plant-based stormwater management systems such as green roofs are typically composed exclusively of vascular plants. Yet, mosses have several desirable properties that could warrant their more widespread use in green roof applications. In natural systems mosses are important primary colonizers of bare ground, and their establishment improves water storage and provides numerous soil benefits including carbon and nitrogen sequestration. Additionally, mosses often facilitate the establishment and survival of vascular plants at otherwise environmentally harsh or stressful sites. Despite their potential value, few studies have investigated the functional performance of mosses on green roofs. In this study we evaluated the establishment success and potential stormwater performance of three candidate moss species. We also directly compared the runoff and thermal characteristics of replicate moss covered green roofs to vascular planted and bare roofs. Candidate mosses had high water holding capacities, storing 8–10 times their weight in water compared to only 1.3 times for typical green roof medium. Mock-up roof sections composed of mosses and medium had delayed and reduced runoff flows relative to medium only sections, although the magnitude of these effects varied with moss species. In field trials all three mosses survived a harsh rooftop environment with limited summer irrigation, although lateral growth after one year was minimal. Green roofs planted solely with Racomitrium canescens had between 12–24% higher stormwater retention than vascular or medium only roofs. Moss cover also ameliorated temperature fluctuations on green roofs. Hourly heating rates were buffered to a similar degree (less than half that of surface temperatures) 5 cm below the surface of both moss covered and medium only roofs. In contrast, cooling under the surface of the moss roof was nearly 6 times faster than under the medium only roof. These results demonstrate the potential for mosses to be valuable components of green roofs, either in combination with vascular plants or planted exclusively.