Virtually connected, practically mobile

This is the post-print version of the Chapter. The official published version can be accessed from the links below - Copyright @ 2006 SpringerThis chapter addresses a central issue in studies of mobile work and mobile technology – what is the work of mobile workers, and how do they use the resources that they have to undertake this work (i.e. the work they have to do in order to do their work)? In contrast to many of the other papers in this collection, the objective of this chapter is to examine individual mobile work, and not teamwork and co-operation other than where it impacts on the work of individuals. We present data from a study of mobile workers, examining a range of mobile workers to produce a rich picture of their work. Our analysis reveals insights into how mobile workers mix their mobility with their work, home and social lives, their use of mobile technology, the problems – technological and otherwise – inherent in being mobile, and the strategies that they use to manage their work, time, other resources and availability. Our findings demonstrate important issues in understanding mobile work, including the maintenance of communities of practice, the role and management of interpersonal awareness and co-ordination, how environmental resources affect activity, the impact of mobility on family/social relationships and the crossover between the mobile workers’ private and working lives, how preplanning is employed prior to travel, and how mobile workers perform activity multitasking, for example through making use of ‘dead time’. Finally, we turn to the implications of this data for the design and deployment of mobile virtual work (MVW) technologies for individuals and a broader organisational context

The Stringy Quantum Hall Fluid

Using branes in massive Type IIA string theory, and a novel decoupling limit, we provide an explicit correspondence between non-commutative Chern-Simons theory and the fractional quantum Hall fluid. The role of the electrons is played by D-particles, the background magnetic field corresponds to a RR 2-form flux, and the two-dimensional fluid is described by non-commutative D2-branes. The filling fraction is given by the ratio of the number of D2-branes and the number of D8-branes, and therefore by the ratio rank/level of the Chern-Simons gauge theory. Quasiparticles and quasiholes are realized as endpoints of fundamental strings on the D2-branes, and are found to possess fractional D-particle charges and fractional statistics.Comment: 24 pages, 2 figures; references adde

Globular Clusters in NGC 4365: New K-band Imaging and a Reassessment of the Case for Intermediate-age Clusters

We study the globular cluster (GC) system of the Virgo giant elliptical galaxy NGC 4365, using new wide-field VIK imaging. The GC colour distribution has (at least) two peaks, but the colours of the red GCs appear more strongly weighted towards intermediate colours compared to most other large ellipticals and the integrated galaxy light. The intermediate-color/red peak may itself be composed of two sub-populations, with clusters of intermediate colours more concentrated towards the centre of the galaxy than both the blue and red GCs. Nearly all intermediate-colour and red GCs in our sample show an offset towards red V-K and/or blue V-I colours compared to SSP models for old ages in a (V-K,V-I) diagram. This has in the past been interpreted as evidence for intermediate ages. We also combine our VIK data with previously published spectroscopy. The differences between observed and model colour-metallicity relations are consistent with the offsets observed in the two-colour diagram, with the metal-rich GCs being too red (by about 0.2 mag) in V-K and too blue (by about 0.05 mag) in V-I compared to the models at a given metallicity. These offsets cannot easily be explained as an effect of younger ages. We conclude that, while intermediate GC ages cannot be definitively ruled out, an alternative scenario is more likely whereby all the GCs are old but the relative number of intermediate-metallicity GCs is greater than typical for giant ellipticals. The main obstacle to reaching a definitive conclusion is the lack of robust calibrations of integrated spectral and photometric properties for stellar populations with near-solar metallicity. In any case, it is puzzling that the intermediate-colour GCs in NGC 4365 are not accompanied by a corresponding shift of the integrated galaxy light towards bluer colours.Comment: 23 pages, including 20 figures and 5 tables. Accepted for publication in A&

A manipulator arm for zero-g simulations

A 12-ft counterbalanced Slave Manipulator Arm (SMA) was designed and fabricated to be used for resolving the questions of operational applications, capabilities, and limitations for such remote manned systems as the Payload Deployment and Retrieval Mechanism (PDRM) for the shuttle, the Free-Flying Teleoperator System, the Advanced Space Tug, and Planetary Rovers. As a developmental tool for the shuttle manipulator system (or PDRM), the SMA represents an approximate one-quarter scale working model for simulating and demonstrating payload handling, docking assistance, and satellite servicing. For the Free-Flying Teleoperator System and the Advanced Tug, the SMA provides a near full-scale developmental tool for satellite servicing, docking, and deployment/retrieval procedures, techniques, and support equipment requirements. For the Planetary Rovers, it provides an oversize developmental tool for sample handling and soil mechanics investigations. The design of the SMA was based on concepts developed for a 40-ft NASA technology arm to be used for zero-g shuttle manipulator simulations

Detailed abundances from integrated-light spectroscopy: Milky Way globular clusters

We test the performance of our analysis technique for integrated-light spectra by applying it to seven well-studied Galactic GCs that span a wide range of metallicities. Integrated-light spectra were obtained by scanning the slit of the UVES spectrograph on the ESO Very Large Telescope across the half-light diameters of the clusters. We modelled the spectra using resolved HST colour-magnitude diagrams (CMDs), as well as theoretical isochrones, in combination with standard stellar atmosphere and spectral synthesis codes. The abundances of Fe, Na, Mg, Ca, Ti, Cr, and Ba were compared with literature data for individual stars in the clusters. The typical differences between iron abundances derived from our integrated-light spectra and those compiled from the literature are less than 0.1 dex. A larger difference is found for one cluster (NGC 6752), and is most likely caused primarily by stochastic fluctuations in the numbers of bright red giants within the scanned area. As expected, the alpha-elements (Ca, Ti) are enhanced by about 0.3 dex compared to the Solar-scaled composition, while the [Cr/Fe] ratios are close to Solar. When using up-to-date line lists, our [Mg/Fe] ratios also agree well with literature data. Our [Na/Fe] ratios are, on average, 0.08-0.14 dex lower than average values quoted in the literature, and our [Ba/Fe] ratios may be overestimated by 0.20-0.35 dex at the lowest metallicities. We find that analyses based on theoretical isochrones give very similar results to those based on resolved CMDs. Overall, the agreement between our integrated-light abundance measurements and the literature data is satisfactory. Refinements of the modelling procedure, such as corrections for stellar evolutionary and non-LTE effects, might further reduce some of the remaining offsets.Comment: 35 pages, 16 figures, accepted for A&

Effects of Portfolio Planning Methods on Decision Making: Experimental Results*

Subjects (n = 1015) working individually in the role of managers were asked to choose between investment opportunities that would either double their investment or cause the loss of half of it. Six administrators ran experiments on 27 occasions in six countries over a five-year period. Information about the BCG matrix increased the subjects' likelihood of selecting the project that was clearly less profitable. Of subjects exposed to the BCG matrix, 64% selected the unprofitable investment. Of subjects who used the BCG matrix in their analysis, 87% selected the less profitable investment.decision making, marketing, portfolio planning methods

Forecasting for Marketing

Research on forecasting is extensive and includes many studies that have tested alternative methods in order to determine which ones are most effective. We review this evidence in order to provide guidelines for forecasting for marketing. The coverage includes intentions, Delphi, role playing, conjoint analysis, judgmental bootstrapping, analogies, extrapolation, rule-based forecasting, expert systems, and econometric methods. We discuss research about which methods are most appropriate to forecast market size, actions of decision makers, market share, sales, and financial outcomes. In general, there is a need for statistical methods that incorporate the manager's domain knowledge. This includes rule-based forecasting, expert systems, and econometric methods. We describe how to choose a forecasting method and provide guidelines for the effective use of forecasts including such procedures as scenarios.forecasting, marketing

Portfolio Planning Methods: Faulty Approach or Faulty Research? A Rejoinder to 'Making Better Decisions' by Wensley

Wensley (1994) makes three key points. First, it is worthwhile to conduct empirical studies of the value of management techniques. Second, managers probably misuse portfolio methods. Third, the Armstrong and Brodie study is flawed. We agree with all three points.marketing, portfolio planning methods

Hypotheses in Marketing Science: Literature Review and Publication Audit

We examined three approaches to research in marketing: exploratory hypotheses, dominant hypothesis, and competing hypotheses. Our review of empirical studies on scientific methodology suggests that the use of a single dominant hypothesis lacks objectivity relative to the use of exploratory and competing hypotheses approaches. We then conducted a publication audit of over 1,700 empirical papers in six leading marketing journals during 1984-1999. Of these, 74% used the dominant hypothesis approach, while 13 % used multiple competing hypotheses, and 13% were exploratory. Competing hypotheses were more commonly used for studying methods (25%) than models (17%) and phenomena (7%). Changes in the approach to hypotheses since 1984 have been modest; there was a slight decrease in the percentage of competing hypotheses to 11%, which is plained primarily by an increasing proportion of papers on phenomena. Of the studies based on hypothesis testing, only 11 % described the conditions under which the hypotheses would apply, and dominant hypotheses were below competing hypotheses in this regard. Marketing scientists differed substantially in their opinions about what types of studies should be published and what was published. On average, they did not think dominant hypotheses should be used as often as they were, and they underestimated their use