Organizational Control Systems and Software Quality: A Cross-National Study.

This study explores the relationship between organizational control modes (behavior, outcome, and clan) andsoftware quality. Much of the previous work on organizational control has examined the choice of modes giventask characteristics. This research extends work in control theory by considering the impact of control modeson the increasingly critical organizational outcome of software quality. The research is set in the context ofsoftware development organizations in three of the largest software developing countries: India, Ireland, andIsrael (the 3Is). A cross sectional survey of 400 software development organizations across the 3Is will be usedto test the developed model. In addition to the theoretical contributions, the study will provide practicalimplications to support software project managers in making better organizational control choices

Evolution of helicity in NOAA 10923 over three consecutive solar rotations

We have studied the evolution of magnetic helicity and chirality in an active region over three consecutive solar rotations. The region when it first appeared was named NOAA10923 and in subsequent rotations it was numbered NOAA 10930, 10935 and 10941. We compare the chirality of these regions at photospheric, chromospheric and coronal heights. The observations used for photospheric and chromospheric heights are taken from Solar Vector Magnetograph (SVM) and H_alpha imaging telescope of Udaipur Solar Observatory (USO), respectively. We discuss the chirality of the sunspots and associated H_alpha filaments in these regions. We find that the twistedness of superpenumbral filaments is maintained in the photospheric transverse field vectors also. We also compare the chirality at photospheric and chromospheric heights with the chirality of the associated coronal loops, as observed from the HINODE X-Ray Telescope.Comment: 8 pages, 4 figure

On the flare induced seismicity in the active region NOAA 10930 and related enhancement of global waves in the sun

A major flare (of class X3.4) occurred on 13 December 2006 in the active region NOAA 10930. The energy released during flares is also known to induce acoustic oscillations in the Sun. Here, we analyze the line-of-sight velocity patterns in this active region during the X3.4 flare using the Dopplergrams obtained by GONG instrument. We have also analyzed the disk-integrated velocity observations of the Sun obtained by GOLF instrument onboard SOHO spacecraft as well as full-disk collapsed velocity signals from GONG observations during this flare to study any possible connection between the flare related changes seen in the local and global velocity oscillations in the Sun. We apply wavelet transform to the time series of the localized velocity oscillations as well as the global velocity oscillations in the Sun spanning the flare event. The line-of-sight velocity shows significant enhancement in some localized regions of the penumbra of this active region during the flare. The affected region is seen to be away from the locations of the flare ribbons and the hard X-ray footpoints. The sudden enhancement in this velocity seems to be caused by the Lorentz force driven by the "magnetic jerk" in the localized penumbral region. Application of wavelet analysis to these flare induced localized seismic signals show significant enhancement in the high-frequency domain (5-8 mHz) and a feeble enhancement in the p-mode oscillations (2-5 mHz) during the flare. On the other hand, the wavelet analysis of GOLF velocity data and the full-disk collapsed GONG velocity data spanning the flare event indicate significant post-flare enhancements in the high-frequency global velocity oscillations in the Sun. We find indications of a connection between flare induced localized seismic signals and the excitation of global high-frequency oscillations in the Sun.Comment: 29 pages, 7 figures, To appear in The Astrophysical Journa

First Use of Synoptic Vector Magnetograms for Global Nonlinear, Force-Free Coronal Magnetic Field Models

Context. The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Currently, there are several modelling techniques being used to calculate three-dimensional field lines into the solar atmosphere. Aims. For the first time, synoptic maps of a photospheric-vector magnetic field synthesized from the vector spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) are used to model the coronal magnetic field and estimate free magnetic energy in the global scale. The free energy (i.e., the energy in excess of the potential field energy) is one of the main indicators used in space weather forecasts to predict the eruptivity of active regions. Methods. We solve the nonlinear force-free field equations using an optimization principle in spherical geometry. The resulting threedimensional magnetic fields are used to estimate the magnetic free energy content E(sub free) = E(sub nlfff) E(sub pot), which is the difference of the magnetic energies between the nonpotential field and the potential field in the global solar corona. For comparison, we overlay the extrapolated magnetic field lines with the extreme ultraviolet (EUV) observations by the atmospheric imaging assembly (AIA) on board the Solar Dynamics Observatory (SDO). Results. For a single Carrington rotation 2121, we find that the global nonlinear force-free field (NLFFF) magnetic energy density is 10.3% higher than the potential one. Most of this free energy is located in active regions