Identifying Agile Requirements Engineering Patterns in Industry

Agile Software Development (ASD) is gaining in popularity in today´s business world. Industry is adopting agile methodologies both to accelerate value delivery and to enhance the ability to deal with changing requirements. However, ASD has a great impact on how Requirements Engineering (RE) is carried out in agile environments. The integration of Human-Centered Design (HCD) plays an important role due to the focus on user and stakeholder involvement. To this end, we aim to introduce agile RE patterns as main objective of this paper. On the one hand, we will describe our pattern mining process based on empirical research in literature and industry. On the other hand, we will discuss our results and provide two examples of agile RE patterns. In sum, the pattern mining process identifies 41 agile RE patterns. The accumulated knowledge will be shared by means of a web application.Ministerio de Economía y Competitividad TIN2013-46928-C3-3-RMinisterio de Economía y Competitividad TIN2016-76956-C3-2-RMinisterio de Economía y Competitividad TIN2015-71938-RED

Neutrophil String Formation: Hydrodynamic Thresholding and Cellular Deformation during Cell Collisions

Neutrophils unexpectedly display flow-enhanced adhesion (hydrodynamic thresholding) to L-selectin in rolling or aggregation assays. We report that the primary collision efficiency (ε) of flowing neutrophils with preadhered neutrophils on intercellular adhesion molecule-1 (ICAM-1) or fibrinogen also displayed a maximum of ε ~ 0.4–0.45 at a wall shear rate of 100 s-1, an example of thresholding. Primary collision lifetime with no detectable bonding decreased from 130 to 10 ms as wall shear rate increased from 30 to 300 s-1, whereas collision lifetimes with bonding decreased from 300 to 100 ms over this shear range using preadhered neutrophils on ICAM-1, with similar results for fibrinogen. Antibodies against L-selectin, but not against CD11a, CD11b, or CD18, reduced ε at 100 s-1 by \u3e85%. High resolution imaging detected large scale deformation of the flowing neutrophil during the collision at 100 s-1 with the apparent contact area increasing up to ~40 μm2. We observed the formation of long linear string assemblies of neutrophils downstream of neutrophils preadhered to ICAM-1, but not fibrinogen, with a maximum in string formation at 100 s-1. Secondary capture events to the ICAM-1 or fibrinogen coated surfaces after primary collisions were infrequent and short lived, typically lasting from 500 to 3500 ms. Between 5 and 20% of neutrophil interactions with ICAM-1 substrate converted to firm arrest (\u3e3500 ms) and greatly exceeded that observed for fibrinogen, thus defining the root cause of poor string formation on fibrinogen at all shear rates. Additionally, neutrophils mobilized calcium after incorporation into strings. Static adhesion also caused calcium mobilization, as did the subsequent onset of flow. To our knowledge, this is the first report of 1), hydrodynamic thresholding in neutrophil string formation; 2), string formation on ICAM-1 but not on fibrinogen; 3), large cellular deformation due to collisions at a venous shear rate; and 4), mechanosensing through neutrophil β2-integrin/adhesion. The increased contact area during deformation was likely responsible for the hydrodynamic threshold observed in the primary collision efficiency since no increase in primary collision lifetime was detected as shear forces were increased (for either surface coating)

Self-Organized States in Cellular Automata: Exact Solution

The spatial structure, fluctuations as well as all state probabilities of self-organized (steady) states of cellular automata can be found (almost) exactly and {\em explicitly} from their Markovian dynamics. The method is shown on an example of a natural sand pile model with a gradient threshold.Comment: 4 pages (REVTeX), incl. 2 figures (PostScript

The opposites task: Using general rules to test cognitive flexibility in preschoolers

A brief narrative description of the journal article, document, or resource. Executive functions play an important role in cognitive development, and during the preschool years especially, children's performance is limited in tasks that demand flexibility in their behavior. We asked whether preschoolers would exhibit limitations when they are required to apply a general rule in the context of novel stimuli on every trial (the "opposites" task). Two types of inhibitory processing were measured: response interference (resistance to interference from a competing response) and proactive interference (resistance to interference from a previously relevant rule). Group data show 3-year-olds have difficulty inhibiting prepotent tendencies under these conditions, whereas 5-year-olds' accuracy is near ceiling in the task. (Contains 4 footnotes and 1 table.

Nonlinear shock acceleration beyond the Bohm limit

We suggest a physical mechanism whereby the acceleration time of cosmic rays by shock waves can be significantly reduced. This creates the possibility of particle acceleration beyond the knee energy at ~10^15eV. The acceleration results from a nonlinear modification of the flow ahead of the shock supported by particles already accelerated to the knee momentum at p ~ p_*. The particles gain energy by bouncing off converging magnetic irregularities frozen into the flow in the shock precursor and not so much by re-crossing the shock itself. The acceleration rate is thus determined by the gradient of the flow velocity and turns out to be formally independent of the particle mean free path (m.f.p.). The velocity gradient is, in turn, set by the knee-particles at p ~ p_* as having the dominant contribution to the CR pressure. Since it is independent of the m.f.p., the acceleration rate of particles above the knee does not decrease with energy, unlike in the linear acceleration regime. The reason for the knee formation at p ~ p_* is that particles with $p > p_*$ are effectively confined to the shock precursor only while they are within limited domains in the momentum space, while other particles fall into ``loss-islands'', similar to the ``loss-cone'' of magnetic traps. This structure of the momentum space is due to the character of the scattering magnetic irregularities. They are formed by a train of shock waves that naturally emerge from unstably growing and steepening magnetosonic waves or as a result of acoustic instability of the CR precursor. These losses steepen the spectrum above the knee, which also prevents the shock width from increasing with the maximum particle energy.Comment: aastex, 13 eps figure

Randomized Benchmarking using Non-Destructive Readout in a 2D Atom Array

Neutral atoms are a promising platform for scalable quantum computing, however prior demonstration of high fidelity gates or low-loss readout methods have employed restricted numbers of qubits. Using randomized benchmarking of microwave-driven single-qubit gates, we demonstrate single qubit gate errors of $8(2)\times10^{-5}$ on 225 atoms using conventional, destructive readout. This exceeds the threshold for fault-tolerance. We further demonstrate suppression of measurement errors via low-loss, non-destructive and state-selective readout on 49 atoms. This enables post-selection for atom loss, which is a primary source of errors in present setups.Comment: 6 pages, 4 figures plus Supplementary Materia

Consumer credit information systems: A critical review of the literature. Too little attention paid by lawyers?

This paper reviews the existing literature on consumer credit reporting, the most extensively used instrument to overcome information asymmetry and adverse selection problems in credit markets. Despite the copious literature in economics and some research in regulatory policy, the legal community has paid almost no attention to the legal framework of consumer credit information systems, especially within the context of the European Union. Studies on the topic, however, seem particularly relevant in view of the establishment of a single market for consumer credit. This article ultimately calls for further legal research to address consumer protection concerns and inform future legislation

Towards a Simple Model of Compressible Alfvenic Turbulence

A simple model collisionless, dissipative, compressible MHD (Alfvenic) turbulence in a magnetized system is investigated. In contrast to more familiar paradigms of turbulence, dissipation arises from Landau damping, enters via nonlinearity, and is distributed over all scales. The theory predicts that two different regimes or phases of turbulence are possible, depending on the ratio of steepening to damping coefficient (m_1/m_2). For strong damping (|m_1/m_2|<1), a regime of smooth, hydrodynamic turbulence is predicted. For |m_1/m_2|>1, steady state turbulence does not exist in the hydrodynamic limit. Rather, spikey, small scale structure is predicted.Comment: 6 pages, one figure, REVTeX; this version to be published in PRE. For related papers, see http://sdphpd.ucsd.edu/~medvedev/papers.htm

Performing heritage: the use of live 'actors' in heritage presentations

This paper investigates the phenomenon of 'living history' presentations of heritage, using live 'actors' to portray historical characters. Its aim is to discuss these presentations in the context of what may be understood as 'heritage', and of the nature of 'performance'. Four case studies of heritage sites, each important as a tourist attraction, have been selected for detailed study, together with a number of other examples of heritage performance. It is clear from the empirical work that different performance strategies are employed within the heritage industry and by individual 'actors'. Most of the performers take part as a leisure activity, and many do not consider themselves to be 'performing' at all. The greatest concern of participants lies in the degree of authenticity of the performance. Through 'living history', the 'actors' are drawn into an experience of heritage which has real meaning for them, and which may contribute both to a sense of identity and to an enhanced understanding of society, past and present. The popularity of such presentations with visitors also indicates that similar benefits are perceived by the 'audience'

Nonlinear turbulent magnetic diffusion and effective drift velocity of large-scale magnetic field in a two-dimensional magnetohydrodynamic turbulence

We study a nonlinear quenching of turbulent magnetic diffusion and effective drift velocity of large-scale magnetic field in a developed two-dimensional MHD turbulence at large magnetic Reynolds numbers. We show that transport of the mean-square magnetic potential strongly changes quenching of turbulent magnetic diffusion. In particularly, the catastrophic quenching of turbulent magnetic diffusion does not occur for the large-scale magnetic fields $B \gg B_{\rm eq} / \sqrt{\rm Rm}$ when a divergence of the flux of the mean-square magnetic potential is not zero, where $B_{\rm eq}$ is the equipartition mean magnetic field determined by the turbulent kinetic energy and Rm is the magnetic Reynolds number. In this case the quenching of turbulent magnetic diffusion is independent of magnetic Reynolds number. The situation is similar to three-dimensional MHD turbulence at large magnetic Reynolds numbers whereby the catastrophic quenching of the alpha effect does not occur when a divergence of the flux of the small-scale magnetic helicity is not zero.Comment: 8 pages, Physical Review E, in pres