Analysis and Design of Class-E3F and Transmission-Line Class-E3F2 Power Amplifiers

In this paper, analysis and synthesis approach for two new variants within the Class-EF power amplifier (PA) family is elaborated. These amplifiers are classified here as Class-E3 F2 and transmission-line (TL) Class-E3 F 2. The proposed circuits offer means to alleviate some of the major issues faced by existing topologies such as substantial power losses due to the parasitic resistance of the large inductor in the Class-EF load network and deviation from ideal Class-EF operation due to the effect of device output inductance at high frequencies. Both lumped-element and transmission-line load networks for the Class-E 3 F PA are described. The load networks of the Class-E3 F and TL Class-E 3 F2amplifier topologies developed in this paper simultaneously satisfy the Class-EF optimum impedance requirements at fundamental frequency, second, and third harmonics as well as simultaneously providing matching to the circuit optimum load resistance for any prescribed system load resistance. Optimum circuit component values are analytically derived and validated by harmonic balance simulations. Trade-offs between circuit figures of merit and component values with some practical limitations being considered are discussed. © 2010 IEEE.

The Outcomes of Cross-Cultural Adjustment: A Case of British Expatriates Working on International Architectural, Engineering and Construction Assignments

The main aim of this study is to investigate the consequences of cross-cultural adjustment in an under researched sample of British expatriates working on International Architectural, Engineering and Construction (AEC) assignments. Adjustment is the primary outcome of an expatriate assignment. According to Bhaskar-Srinivas et al., (2005), Harrison et al., (2004) it is viewed to affect other work related outcomes which could eventually predict expatriate success. To address the scarcity of literature on expatriate management in the AEC sector, an exploratory design was adopted. Phase one is characterised by extensive review of extant literature, whereas phase two was qualitative exploration from British expatriates’ perspective; here seven unstructured interviews were carried out. Further, cognitive mapping analysis through Banaxia decision explorer software was conducted to develop a theoretical framework and propose various hypotheses. The findings imply that British AEC firms could sustain their already established competitive advantage in the global marketplace by acknowledging the complexity of international assignments, prioritising expatriate management and offering a well-rounded support to facilitate expatriate adjustment and ultimately achieve critical outcomes like performance, assignment completion and job satisfaction.

The outcomes of cross-cultural adjustment: A case of British expatriates working on international architectural, engineering and construction assignments

The main aim of this study is to investigate the consequences of cross-cultural adjustment in an under researched sample of British expatriates working on International Architectural, Engineering and Construction (AEC) assignments. Adjustment is the primary outcome of an expatriate assignment. According to Bhaskar-Srinivas et al., (2005), Harrison et al., (2004) it is viewed to affect other work related outcomes which could eventually predict expatriate success. To address the scarcity of literature on expatriate management in the AEC sector, an exploratory design was adopted. Phase one is characterised by extensive review of extant literature, whereas phase two was qualitative exploration from British expatriatesÕ perspective; here seven unstructured interviews were carried out. Further, cognitive mapping analysis through Banaxia decision explorer software was conducted to develop a theoretical framework and propose various hypotheses. The findings imply that British AEC firms could sustain their already established competitive advantage in the global marketplace by acknowledging the complexity of international assignments, prioritising expatriate management and offering a well-rounded support to facilitate expatriate adjustment and ultimately achieve critical outcomes like performance, assignment completion and job satisfaction.

Partial shoeprint retrieval using multiple point-of-interest detectors and SIFT descriptors

Shoeprint evidence collected from crime scenes can play an important role in forensic investigations. Usually, the analysis of shoeprints is carried out manually and is based on human expertise and knowledge. As well as being error prone, such a manual process can also be time consuming; thus affecting the usability and suitability of shoeprint evidence in a court of law. Thus, an automatic system for classification and retrieval of shoeprints has the potential to be a valuable tool. This paper presents a solution for the automatic retrieval of shoeprints which is considerably more robust than existing solutions in the presence of geometric distortions such as scale, rotation and scale distortions. It addresses the issue of classifying partial shoeprints in the presence of rotation, scale and noise distortions and relies on the use of two local point-of-interest detectors whose matching scores are combined. In this work, multiscale Harris and Hessian detectors are used to select corners and blob-like structures in a scale-space representation for scale invariance, while Scale Invariant Feature Transform (SIFT) descriptor is employed to achieve rotation invariance. The proposed technique is based on combining the matching scores of the two detectors at the score level. Our evaluation has shown that it outperforms both detectors in most of our extended experiments when retrieving partial shoeprints with geometric distortions, and is clearly better than similar work published in the literature. We also demonstrate improved performance in the face of wear and tear. As matter of fact, whilst the proposed work outperforms similar algorithms in the literature, it is shown that achieving good retrieval performance is not constrained by acquiring a full print from a scene of crime as a partial print can still be used to attain comparable retrieval results to those of using the full print. This gives crime investigators more flexibility is choosing the parts of a print to search for in a database of footwear.

The Application of Semiconductor Photocatalysis for the Removal of Cyanotoxins from Water and Design Concepts for Solar Photocatalytic Reactors for Large Scale Water Treatment

There has been a significant increase in the occurrence of cyanobacterial blooms in freshwaters over the past few decades due to escalating nutrient levels. These cyanobacteria release a range of toxins, for example microcystins which are chemically very stable. Many cyanotoxins are consequently very difficult to remove from water using existing treatment technologies. Semiconductor photocatalysis, however, has proven to be a very effective process for the removal of these compounds from water. In this chapter we consider the application of this highly versatile and exciting technology for the decomposition of cyanotoxins. Furthermore design concepts for solar photocatalytic reactors that could be utilized for the removal of these toxins are also considered

Barriers to student computer usage: staff and student perceptions

Ensuring that all graduates are able to exploit new technologies is a primary goal of all UK universities and a variety of assumptions have underpinned policies designed to promote this goal, This paper explores some of these assumptions through the findings of a. longitudinal study involving a cohort of over 800 university students. The study adopted a student perspective to examine the factors affecting their use of computers over a three year period. Unsurprisingly, the results indicated that situational factors (e.g. access, training and time) influence the extent to which students use computers, but a disparity was found in the importance attributed to these factors by the academic staff, who focused on the needs of their department, and by the students, who focused on their individual needs. Results suggest that increased attention to a student perspective may lead to improved strategic planning in students' use of computers.