Examining perceptions of agility in software development practice

This is the post-print version of the final published article that is available from the link below. Copyright @ 2010 ACM.Organizations undertaking software development are often reminded that successful practice depends on a number of non-technical issues that are managerial, cultural and organizational in nature. These issues cover aspects from appropriate corporate structure, through software process development and standardization to effective collaborative practice. Since the articulation of the 'software crisis' in the late-1960s, significant effort has been put into addressing problems related to the cost, time and quality of software development via the application of systematic processes and management practices for software engineering. Early efforts resulted in prescriptive structured methods, which have evolved and expanded over time to embrace consortia/ company-led initiatives such as the Unified Modeling Language and the Unified Process alongside formal process improvement frameworks such as the International Standards Organization's 9000 series, the Capability Maturity Model and SPICE. More recently, the philosophy behind traditional plan-based initiatives has been questioned by the agile movement, which seeks to emphasize the human and craft aspects of software development over and above the engineering aspects. Agile practice is strongly collaborative in its outlook, favoring individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a plan (see Sidebar 1). Early experience reports on the use of agile practice suggest some success in dealing with the problems of the software crisis, and suggest that plan-based and agile practice are not mutually exclusive. Indeed, flexibility may arise from this unlikely marriage in an aim to strike a balance between the rigor of traditional plan-based approaches and the need for adaptation of those to suit particular development situations. With this in mind, this article surveys the current practice in software engineering alongside perceptions of senior development managers in relation to agile practice in order to understand the principles of agility that may be practiced implicitly and their effects on plan-based approach

Discontinuous high-order finite-volume/finite-element method for inviscid compressible flows

The discontinuous, hybrid control-volume/finite-element method merges the desirable conservative properties and intuitive physical formulation of the finite-volume technique, with the capability of local arbitrary high-order accuracy distinctive of the discontinuous finite-element method. This relatively novel scheme has been previously applied to the solution of advection-diffusion problems and the shallow-water equations, and is in the present work extended to the Euler equations. The derivation of the method is presented in the general multi-dimensional case, and selected numerical problems are solved in the one- and two-dimensional case

Uniform and fast switching of window-size smectic A liquid crystal panels utilising the field gradient generated at the fringes of patterned electrodes

A method to enable smectic A (SmA) liquid crystal (LC) devices to switch uniformly and hence fast from the clear state to a scattered state is presented. It will allow the reduction of the switching time for a SmA LC panel of 1x1 m2 changing from a clear state to a fully scattered state by more than three orders to a few tens of milliseconds. Experimental results presented here reveal that SmA LC scattering initiates from the nucleated LC defects at the field gradient of the applied electric field usually along the edges of the panel electrode and grows laterally to spread over a panel, which takes a long time if the panel size is large. By patterning the electrodes in use, it is possible to create a large number of field gradient sites near the electrode discontinuities, resulting in a uniform and fast switching over the whole panel and the higher the pattern density the shorter the panel switching time. For the SmA LC panels used here, the ITO transparent electrodes are patterned by laser ablation and photolithography, respectively. It is shown that the defect nucleation time is much shorter than the growth time of the scattered region, hence it is possible to use the density of the field gradient sites to control the uniformity and switching time of a panel. Furthermore, the patterned SmA panels have a lower switching voltage than that of the non-patterned ones in general.The authors would like to thank the UK Engineering and Physical Sciences Research Council (EPSRC) for the support through the Platform Grant for Liquid Crystal Photonics (EP/F00897X/1) and Dr Anthony Davey for providing the organic SmA LC and Dow Corning Corp. for providing the siloxane-based SmA LC used in this study. The authors would also like to thank Dr Stuart Speakman for the helpful discussions.This is the final version of the article. It first appeared from Taylor & Francis via http://dx.doi.org/10.1080/02678292.2016.114201

Fluctuating and dissipative dynamics of dark solitons in quasi-condensates

The fluctuating and dissipative dynamics of matter-wave dark solitons within harmonically trapped, partially condensed Bose gases is studied both numerically and analytically. A study of the stochastic Gross-Pitaevskii equation, which correctly accounts for density and phase fluctuations at finite temperatures, reveals dark soliton decay times to be lognormally distributed at each temperature, thereby characterizing the previously predicted long lived soliton trajectories within each ensemble of numerical realizations (S.P. Cockburn {\it et al.}, Phys. Rev. Lett. 104, 174101 (2010)). Expectation values for the average soliton lifetimes extracted from these distributions are found to agree well with both numerical and analytic predictions based upon the dissipative Gross-Pitaevskii model (with the same {\it ab initio} damping). Probing the regime for which $0.8 k_{B}T < \mu < 1.6 k_{B}T$, we find average soliton lifetimes to scale with temperature as $\tau\sim T^{-4}$, in agreement with predictions previously made for the low-temperature regime $k_{B}T\ll\mu$. The model is also shown to capture the experimentally-relevant decrease in the visibility of an oscillating soliton due to the presence of background fluctuations.Comment: 17 pages, 14 figure

High-Order Discontinuous Galerkin Method for Boltzmann Model Equations

High-order Runge-Kutta discontinuous Galerkin (DG) method is applied to the kinetic model equations describing rarefied gas flows. A conservative DG discretization of nonlinear collision relaxation term is formulated for Bhatnagar-Gross-Krook and ellipsoidal statistical models. The numerical solutions using RKDG method of order up to four are obtained for two flow problems: the heat transfer between parallel plates and the normal shock wave. The convergence of RKDG method is compared with the conventional secondorder finite volume method for the heat transfer problem. The normal shock wave solutions obtained using RKDG are compared with the experimental measurements of density and velocity distribution function inside the shock

A posteriori error analysis and adaptive non-intrusive numerical schemes for systems of random conservation laws

In this article we consider one-dimensional random systems of hyperbolic conservation laws. We first establish existence and uniqueness of random entropy admissible solutions for initial value problems of conservation laws which involve random initial data and random flux functions. Based on these results we present an a posteriori error analysis for a numerical approximation of the random entropy admissible solution. For the stochastic discretization, we consider a non-intrusive approach, the Stochastic Collocation method. The spatio-temporal discretization relies on the Runge--Kutta Discontinuous Galerkin method. We derive the a posteriori estimator using continuous reconstructions of the discrete solution. Combined with the relative entropy stability framework this yields computable error bounds for the entire space-stochastic discretization error. The estimator admits a splitting into a stochastic and a deterministic (space-time) part, allowing for a novel residual-based space-stochastic adaptive mesh refinement algorithm. We conclude with various numerical examples investigating the scaling properties of the residuals and illustrating the efficiency of the proposed adaptive algorithm

How should I treat a patient with significant angina and a severe left anterior descending artery stenosis beyond the insertion of a left internal mammary artery jump graft (diagonal to LAD)?

BACKGROUND: A 60-year-old man with a history of previous coronary artery bypass grafting (saphenous vein grafting [SVG] to native right coronary artery [RCA] and sequential left internal mammary artery [LIMA] jump grafting to his native first diagonal [D1] and left anterior descending [LAD] arteries), who had developed a previous ischaemic cerebrovascular accident following femoral angiography, re-presented with further ischaemic cardiac symptoms.\ud \ud INVESTIGATIONS: Physical examination, electrocardiography, biochemistry including high-sensitive troponin, echocardiography, and trans-radial angiography.\ud \ud DIAGNOSIS: Severe native 3 vessel disease including ostial occlusion of the LAD, distal left circumflex and obtuse marginal (LCX/OM) disease and proximal RCA occlusion; occluded SVG to RCA, and evidence of a critical stenosis in the mid LAD distal to the insertion of the tortuous LIMA jump graft (diagonal to LAD).\ud \ud TREATMENT: PCI to mid LAD lesion via LIMA jump graft from left trans-radial approach

Agile methods for agile universities

We explore a term, Agile, that is being used in various workplace settings, including the management of universities. The term may have several related but slightly different meanings. Agile is often used in the context of facilitating more creative problem-solving and advocating for the adoption, design, tailoring and continual updating of more innovative organizational processes. We consider a particular set of meanings of the term from the world of software development. Agile methods were created to address certain problems with the software development process. Many of those problems have interesting analogues in the context of universities, so a reflection on agile methods may be a useful heuristic for generating ideas for enabling universities to be more creative