Developing a taxonomy for the understanding of business and it alignment paradigms and tools

The alignment of information technology with business objectives tends to be a managerial priority in modern organisations. Thus, practitioners and researchers have proposed different approaches to assess this relationship, some following similar approaches whilst others proposing different ones. The variety of approaches proposed, however, has created confusion about the applicability and context in which these approaches can be used. Thus, aiming to tackle this challenge, this paper proposes a taxonomy that organises and compares studies of alignment assessment in terms of their theoretical constructors and their practical use. The taxonomy is build around two research sources: a) a review of the literature of alignment and b) a framework for comparing IS methodologies. The structure of the taxonomy permits insights into studies by means of six theoretical (objective, nature of strategy, paradigm, dimension, type of measurement, model) and six practical constructors (audience, scope, output, techniques, product, target). The taxonomy is then applied to six assessment studies. The benchmarking analysis of these helped to identify their theoretical basis and its practical use, and confirms the need for more practical mechanisms to assess alignment. Additionally, it becomes apparent that process perspectives and social understanding of alignment are the two main paradigms for alignment

Developments in aircraft jet noise technology

Significant developments in two areas of jet noise technology are described: the development of jet noise technology relative to coannular nozzles of all types, and a recent approach to the analysis of flight effects that appears to allow simulated flight effects results to be transformed to actual flight conditions with a high degree of confidence. The coannular nozzle section presents results applicable to high-bypass-ratio turbofan engines, as well as current work on inverted-profile coannular nozzles applicable to low-bypass-ratio turbofan engines suitable for use in future supersonic cruise aircraft

Noise of model target type thrust reversers for engine-over-the-wing applications

The results of experiments on the noise generated by V-gutter and semicylindrical target reversers with circular and short-aspect-ratio slot nozzles having diameters of about 5 cm are presented. The experiments were conducted with cold-flow jets at velocities from 190-290 m/sec. The reversers at subsonic jet velocities had a more uniform noise distribution and higher frequency than the nozzles alone. The reverser shape was shown to be more important than the nozzle shape in determining the noise characteristics. The maximum sideline pressure level varied with the sixth power of the jet velocity, and the data were correlated for angles along the sideline. An estimate of the noise level along the 152 m sideline for an engine-over-the-wing powered-lift airplane was made

Status of noise technology for advanced supersonic cruise aircraft

Developments in acoustic technology applicable to advanced supersonic cruise aircraft, particularly those which relate to jet noise and its suppression are reviewed. The noise reducing potential of high radius ratio, inverted velocity profile coannular jets is demonstrated by model scale results from a wide range of nozzle geometries, including some simulated flight cases. These results were verified statistically at large scale on a variable cycle engine (VCE) testbed. A preliminary assessment of potential VCE noise sources such as fan and core noise is made, based on the testbed data. Recent advances in the understanding of flight effects are reviewed. The status of component noise prediction methods is assessed on the basis of recent test data, and the remaining problem areas are outlined

Noise tests of a high-aspect-ratio slot nozzle with various V-gutter target thrust reversers

The results of experiments on the noise generated by a 1.33- by 91.4 cm slot nozzle with various V-gutter reversers, and some thrust measurements are presented. The experiments were conducted with near-ambient temperature jets at nozzle pressure ratios of 1.25 to 3.0, yielding jet velocities of about 190 to 400 m/sec. At pressure ratios of 2 or less, the reversers, in addition to being noisier than the nozzle alone, also had a more uniform directional distribution and more high-frequency noise. At pressure ratios above 2, the nozzle alone generated enough shock noise that the levels were about the same as for the reversers. The maximum overall sound pressure level and the effective overall sound power level both varied with the sixth power of jet velocity over the range tested. The data were scaled up to a size suitable for reversing the wing-flap slot nozzle flow of a 45 400-kg augmentor-wing-type airplane on the ground, yielding perceived noise levels well above 95 PNdB on a 152-m sideline