Perturbed frequency selective surfaces for multiband high impedance surfaces

Multiresonant high impedance surfaces (HIS) without grounding vias that perform as artificial magnetic conductors (AMC) in multiple frequency bands and furthermore exhibit electromagnetic band gaps (EBG) in the same bands are presented. This is achieved by introducing perturbed frequency selective surface (FSS) arrays printed on grounded dielectric substrates. Arrays of linear dipoles are employed as an example. Perturbations are introduced by means of reducing the length of every other array element. Starting from the characteristics of a perturbed free-standing FSS, the authors present the effect of the perturbation on the excited currents and on the reflection properties of a corresponding AMC. Conclusions about the performance limitations are derived. Subsequently, a parametric study on practical HIS is presented and an optimised design with dual-band AMC and EBG response is demonstrated. Method of moments-based software has been developed and utilised for the fast and accurate analysis of such arrays. Experimental results validate the performance of the optimised structure.

Handling Inconsistency In Distributed Software Requirements Specifications Based On Prioritized Merging

Developing a desirable framework for handling inconsistencies in software requirements specifications is a challenging problem. It has been widely recognized that the relative priority of requirements can help developers to make some necessary trade-off decisions for resolving con- flicts. However, for most distributed development such as viewpoints-based approaches, different stakeholders may assign different levels of priority to the same shared requirements statement from their own perspectives. The disagreement in the local levels of priority assigned to the same shared requirements statement often puts developers into a dilemma during the inconsistency handling process. The main contribution of this paper is to present a prioritized merging-based framework for handling inconsistency in distributed software requirements specifications. Given a set of distributed inconsistent requirements collections with the local prioritization, we first construct a requirements specification with a prioritization from an overall perspective. We provide two approaches to constructing a requirements specification with the global prioritization, including a merging-based construction and a priority vector-based construction. Following this, we derive proposals for handling inconsistencies from the globally prioritized requirements specification in terms of prioritized merging. Moreover, from the overall perspective, these proposals may be viewed as the most appropriate to modifying the given inconsistent requirements specification in the sense of the ordering relation over all the consistent subsets of the requirements specification. Finally, we consider applying negotiation-based techniques to viewpoints so as to identify an acceptable common proposal from these proposals.

Lean Software Management: BBC Worldwide Case Study

This case study examines how the lean ideas behind the Toyota production system can be applied to software project management. It is a detailed investigation of the performance of a nine-person software development team employed by BBC Worldwide based in London. The data collected in 2009 involved direct observations of the development team, the kanban boards, the daily stand-up meetings, semistructured interviews with a wide variety of staff, and statistical analysis. The evidence shows that over the 12-month period, lead time to deliver software improved by 37%, consistency of delivery rose by 47%, and defects reported by customers fell 24%. The significance of this work is showing that the use of lean methods including visual management, team-based problem solving, smaller batch sizes, and statistical process control can improve software development. It also summarizes key differences between agile and lean approaches to software development. The conclusion is that the performance of the software development team was improved by adopting a lean approach. The faster delivery with a focus on creating the highest value to the customer also reduced both technical and market risks. The drawbacks are that it may not fit well with existing corporate standards.

And He Opened His Mouth and Taught Them Saying

This paper provides an overview of rich biblical imagery related to the mouth, built around the conceptual metaphor MOUTH IS AN OPENING, followed by a critical analysis of four text units from both Testaments employing the basic extensions of this metaphor in the renderings of twelve contemporary English versions of the Bible. It is demonstrated that the meaningful choice of translating techniques and the type of equivalence pursued in translation must be based on a thorough examination and comparison of the conceptual systems of the source and target languages.