118,104 research outputs found

    Is it time to rethink project success?

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    The notion of success and failure in software projects are confusing. Failure is often considered in the context of the iron triangle as the inability to meet time, cost and performance constraints. Yet, while there is a consensus around the prevalence of project failure, new projects seem destined to repeat past mistakes. This paper tries to advance the discussion by offering a new perspective for reasoning about the meaning of success and the different types of software project failures. The paper advocates rising beyond the fixation with internal parameters of efficiency. It begins by discussing the limited insights from existing project failure surveys, before offering a four level model addressing the essence of successful delivery and operation in software projects and considering the different measures required in order to utilise richer measurements of success

    Transverse instability for non-normal parameters

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    We consider the behaviour of attractors near invariant subspaces on varying a parameter that does not preserve the dynamics in the invariant subspace but is otherwise generic, in a smooth dynamical system. We refer to such a parameter as ``non-normal''. If there is chaos in the invariant subspace that is not structurally stable, this has the effect of ``blurring out'' blowout bifurcations over a range of parameter values that we show can have positive measure in parameter space. Associated with such blowout bifurcations are bifurcations to attractors displaying a new type of intermittency that is phenomenologically similar to on-off intermittency, but where the intersection of the attractor by the invariant subspace is larger than a minimal attractor. The presence of distinct repelling and attracting invariant sets leads us to refer to this as ``in-out'' intermittency. Such behaviour cannot appear in systems where the transverse dynamics is a skew product over the system on the invariant subspace. We characterise in-out intermittency in terms of its structure in phase space and in terms of invariants of the dynamics obtained from a Markov model of the attractor. This model predicts a scaling of the length of laminar phases that is similar to that for on-off intermittency but which has some differences.Comment: 15 figures, submitted to Nonlinearity, the full paper available at http://www.maths.qmw.ac.uk/~eo

    A perpetual switching system in pulmonary capillaries

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    Of the 300 billion capillaries in the human lung, a small fraction meet normal oxygen requirements at rest, with the remainder forming a large reserve. The maximum oxygen demands of the acute stress response require that the reserve capillaries are rapidly recruited. To remain primed for emergencies, the normal cardiac output must be parceled throughout the capillary bed to maintain low opening pressures. The flow-distributing system requires complex switching. Because the pulmonary microcirculation contains contractile machinery, one hypothesis posits an active switching system. The opposing hypothesis is based on passive switching that requires no regulation. Both hypotheses were tested ex vivo in canine lung lobes. The lobes were perfused first with autologous blood, and capillary switching patterns were recorded by videomicroscopy. Next, the vasculature of the lobes was saline flushed, fixed by glutaraldehyde perfusion, flushed again, and then reperfused with the original, unfixed blood. Flow patterns through the same capillaries were recorded again. The 16-min-long videos were divided into 4-s increments. Each capillary segment was recorded as being perfused if at least one red blood cell crossed the entire segment. Otherwise it was recorded as unperfused. These binary measurements were made manually for each segment during every 4 s throughout the 16-min recordings of the fresh and fixed capillaries (>60,000 measurements). Unexpectedly, the switching patterns did not change after fixation. We conclude that the pulmonary capillaries can remain primed for emergencies without requiring regulation: no detectors, no feedback loops, and no effectors-a rare system in biology. NEW & NOTEWORTHY The fluctuating flow patterns of red blood cells within the pulmonary capillary networks have been assumed to be actively controlled within the pulmonary microcirculation. Here we show that the capillary flow switching patterns in the same network are the same whether the lungs are fresh or fixed. This unexpected observation can be successfully explained by a new model of pulmonary capillary flow based on chaos theory and fractal mathematics

    The Reception of Hesiod by the Early Presocratics

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    The early Presocratics’ major speculative and critical initiatives—in particular, Anaximander’s conceptions of the justice of the cosmos and of the apeiron as its archē and Xenophanes’s polemics against immorality and anthropomorphism in the depiction of the gods and against any claim to divine inspiration—appear to break with Hesiod’s form of thought. But the conceptual, critical, and ethical depth of Hesiod’s own rethinking of the lore that he inherits complicates this picture. Close examination of each of their major initiatives together with the relevant passages in Hesiod shows that even in the course of departing from his thought, Anaximander and Xenophanes also reappropriate and renew it. In a postscript I pose some questions for future inquiry into Heraclitus’s and Parmenides’s receptions of Hesiod

    Overspend? Late? Failure? What the Data Say About IT Project Risk in the Public Sector

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    Implementing large-scale information and communication technology (IT) projects carries large risks and easily might disrupt operations, waste taxpayers' money, and create negative publicity. Because of the high risks it is important that government leaders manage the attendant risks. We analysed a sample of 1,355 public sector IT projects. The sample included large-scale projects, on average the actual expenditure was $130 million and the average duration was 35 months. Our findings showed that the typical project had no cost overruns and took on average 24% longer than initially expected. However, comparing the risk distribution with the normative model of a thin-tailed distribution, projects' actual costs should fall within -30% and +25% of the budget in nearly 99 out of 100 projects. The data showed, however, that a staggering 18% of all projects are outliers with cost overruns >25%. Tests showed that the risk of outliers is even higher for standard software (24%) as well as in certain project types, e.g., data management (41%), office management (23%), eGovernment (21%) and management information systems (20%). Analysis showed also that projects duration adds risk: every additional year of project duration increases the average cost risk by 4.2 percentage points. Lastly, we suggest four solutions that public sector organization can take: (1) benchmark your organization to know where you are, (2) de-bias your IT project decision-making, (3) reduce the complexities of your IT projects, and (4) develop Masterbuilders to learn from the best in the field.Comment: Published in Commonwealth Secretariat (Eds.): Commonwealth Governance Handbook 2012/13: Democracy, development and public administration, London: Commonwealth Secretariat, December 2012. ISBN 978-1-908609-04-

    Double Whammy - How ICT Projects are Fooled by Randomness and Screwed by Political Intent

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    The cost-benefit analysis formulates the holy trinity of objectives of project management - cost, schedule, and benefits. As our previous research has shown, ICT projects deviate from their initial cost estimate by more than 10% in 8 out of 10 cases. Academic research has argued that Optimism Bias and Black Swan Blindness cause forecasts to fall short of actual costs. Firstly, optimism bias has been linked to effects of deception and delusion, which is caused by taking the inside-view and ignoring distributional information when making decisions. Secondly, we argued before that Black Swan Blindness makes decision-makers ignore outlying events even if decisions and judgements are based on the outside view. Using a sample of 1,471 ICT projects with a total value of USD 241 billion - we answer the question: Can we show the different effects of Normal Performance, Delusion, and Deception? We calculated the cumulative distribution function (CDF) of (actual-forecast)/forecast. Our results show that the CDF changes at two tipping points - the first one transforms an exponential function into a Gaussian bell curve. The second tipping point transforms the bell curve into a power law distribution with the power of 2. We argue that these results show that project performance up to the first tipping point is politically motivated and project performance above the second tipping point indicates that project managers and decision-makers are fooled by random outliers, because they are blind to thick tails. We then show that Black Swan ICT projects are a significant source of uncertainty to an organisation and that management needs to be aware of
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