Surrogate-Based Optimization Using Multifidelity Models with Variable Parameterization and Corrected Space Mapping

Surrogate-based-optimization methods provide a means to achieve high-fidelity design optimization at reduced computational cost by using a high-fidelity model in combination with lower-fidelity models that are less expensive to evaluate. This paper presents a provably convergent trust-region model-management methodology for variableparameterization design models: that is, models for which the design parameters are defined over different spaces. Corrected space mapping is introduced as a method to map between the variable-parameterization design spaces. It is then used with a sequential-quadratic-programming-like trust-region method for two aerospace-related design optimization problems. Results for a wing design problem and a flapping-flight problem show that the method outperforms direct optimization in the high-fidelity space. On the wing design problem, the new method achieves 76% savings in high-fidelity function calls. On a bat-flight design problem, it achieves approximately 45% time savings, although it converges to a different local minimum than did the benchmark.

Real-space mapping of dynamic phenomena during hysteresis loop measurements: Dynamic switching spectroscopy piezoresponse force microscopy

Dynamic switching spectroscopy piezoresponse force microscopy is developed to separate thermodynamic and kinetic effects in local bias-induced phase transitions. The approaches for visualization and analysis of five-dimensional data are discussed. The spatial and voltage variability of relaxation behavior of the a-c domain lead zirconate-titanate surface suggest the interpretation in terms of surface charge dynamics. This approach is applicable to local studies of dynamic behavior in any system with reversible bias-induced phase transitions ranging from ferroelectrics and multiferroics to ionic systems such as batteries, fuel cells, and electroresistive materials. (C) 2011 American Institute of Physics. [doi:10.1063/1.3590919]

Patrick Moore, Arthur C. Clarke and ‘British Outer Space’ in the mid 20th century

This article seeks to explore a notion of 'British outer space' in the mid 20th century with reference to the British Interplanetary Society and the works of Patrick Moore and Arthur C. Clarke. Geographies of outer space have been examined following early work by Denis Cosgrove on the Apollo space photographs. Cosgrove's work has encouraged a growing body of work that seeks to examine both the 'Earth from space' perspective as well as its reciprocal, 'space from Earth'. This article aligns itself with the latter viewpoint, in attempting to define a national culture of 'British outer space'. This is found to have an important connection with the British Interplanetary Society, founded in 1933 near Liverpool, which went on to influence the works of Patrick Moore, who edited the magazine Spaceflight and presented the television programme The Sky at Night, and Arthur C. Clarke, who became known as a science fiction writer through his early novels in the 1950s. The themes of audience participation and human destiny in outer space are examined in a close reading of these two case studies, and further engagement with cultures of outer space in geography is encouraged. © The Author(s) 2012.

Design Method for Circularly Polarized Frequency Selective Surfaces

This paper proposes a design method for the realisation of circularly polarised frequency selective surfaces (CP FSS). An equivalent circuit model for a capacitive asymmetric loop FSS is proposed. For this model a set of nonlinear design equation for CP operation is obtained. Based on space mapping of the model and full-wave simulation, a fast converging design method for CP FSS synthesis is demonstrated for the first time. 

Mapping cosmopolis: moral topographies of the medieval city

Cosmopolis is a concept that has a long history in many cultures around the globe. It is a mirroring of the 'social' and 'natural' worlds, such that in one is seen the order and the structures of the other -- a mutual 'mapping'. In this paper I examine how the presence of cosmopolis -- a Christianised cosmopolis of the European Middle Ages -- was made evident in the representation and formation of cities at that time. I reveal a dualism between the social and spatial ordering of both city and cosmos which defined and reinforced social and spatial boundaries in urban landscapes, evident for example in the 11th and 12th centuries. Recently, Toulmin (1992) has taken the idea of cosmopolis to argue that it has been a persistent presence in Western - Enlightenment science, philosophy, and religion -- a 'hidden agenda of modernity'. I contend that, as an idea, cosmopolis has a much earlier circulation in European thinking, not least in the Middle Ages. Locating cosmopolis in the medieval and the modern periods then begs a question of what is it that really makes the two distinct and separate? All too often human geographers have emphasised discontinuities between the 'medieval' and 'modern' age, locating the 'rise of modernity' some time in the Enlightenment period. However, what 'mapping' cosmopolis reveals are continuities, binding time and space together, which when looked at begin to help query the modernity concept itself.

Cartographic veracity in medieval mapping: analyzing geographical variation in the Gough Map of Great Britain

This article explores statistical approaches for assessing the relative accuracy of medieval mapping. It focuses on one particular map, the Gough Map of Great Britain. This is an early and remarkable example of a medieval “national” map covering Plantagenet Britain. Conventionally dated to c. 1360, the map shows the position of places in and coastal outline of Great Britain to a considerable degree of spatial accuracy. In this article, aspects of the map's content are subjected to a systematic analysis to identify geographical variations in the map's veracity, or truthfulness. It thus contributes to debates among historical geographers and cartographic historians on the nature of medieval maps and mapping and, in particular, questions of their distortion of geographic space. Based on a newly developed digital version of the Gough Map, several regression-based approaches are used here to explore the degree and nature of spatial distortion in the Gough Map. This demonstrates that not only are there marked variations in the positional accuracy of places shown on the map between regions (i.e., England, Scotland, and Wales), but there are also fine-scale geographical variations in the spatial accuracy of the map within these regions. The article concludes by suggesting that the map was constructed using a range of sources, and that the Gough Map is a composite of multiscale representations of places in Great Britain. The article details a set of approaches that could be transferred to other contexts and add value to historic maps by enhancing understanding of their contents.

Stokes imaging, Doppler mapping and Roche tomography of the AM Herculis system V834 Cen

We report on new simultaneous phase-resolved spectroscopic and polarimetric observations of the polar (AM Herculis star) V834 Cen during a high state of accretion. Strong emission lines and high levels of variable circular and linear polarization are observed over the orbital period. The polarization data are modelled using the Stokes imaging technique of Potter et al. The spectroscopic emission lines are investigated using the Doppler tomography technique of Marsh and Horne and the Roche tomography technique of Dhillon and Watson. Up to now, all three techniques have been used separately to investigate the geometry and accretion dynamics in cataclysmic variables. For the first time, we apply all three techniques to simultaneous data for a single system. This allows us to compare and test each of the techniques against each other and hence to derive a better understanding of the geometry, dynamics and system parameters of V834 Cen.

Joint complex diversity coding and channel coding over space, time and frequency

This study provides a general diversity analysis for joint complex diversity coding (CDC) and channel coding-based space-time-frequency codeing is provided. The mapping designs from channel coding to CDC are crucial for efficient exploitation of the diversity potential. This study provides and proves a sufficient condition of full diversity construction with joint three-dimensional CDC and channel coding, bit-interleaved coded complex diversity coding and symbol-interleaved coded complex diversity coding. Both non-iterative and iterative detections of joint channel code and CDC transmission are investigated. The proposed minimum mean-square error-based iterative soft decoding achieves the performance of the soft sphere decoding with reduced complexity.

A silent witness? Medieval urban landscapes and unfolding their mapping histories

This paper offers a critical reflection on the place of maps in writing medieval urban histories. Using findings from recent research on medieval Swansea, the case is made that mapping provides an interpretative space for exploring alternative narratives about past places. To do so the paper draws upon current critical debates on cartography, particularly the idea that mapping is fluid and iterative, to suggest that Swansea's medieval urban origins are open to a range of alternative interpretations. This approach to mapping differs from that often used by historians to map medieval urban landscapes, where historic maps are simply used as ‘sources’, and the landscapes they represent used as ‘witnesses’ to past events, for creating maps, both through digital and analogue media, instead opens up – or unfolds – a landscape's past. The paper uses past attempts to map medieval Swansea to highlight difficulties in interpreting its urban landscape features, and uses multiple mappings of the medieval townscape, resulting from recent research, to question how far any sources about the past really provide a coherent narrative. Instead, multiple mappings of the medieval urban landscape – reflecting different and competing perspectives – are more attuned with how places were perceived and understood during the Middle Ages.

European urban spaces in crisis - the mapping of affective pracitices with Living with Difference: introduction

The introduction outlines the notion of urban space and crisis in Europe while taking into account the more recent protests and riots in different cities, in and beyond Europe. It is argued that the phenomen of protest is happening alongside the economic crisis underscoring an alternative political public civic spirit expressing to a certain degree the renaissance and timely making of, what might be called in the digital age, #œuvre. Its forces and emotional properties capture a political realm that unfolds as a globalized urban transnational public space, still progressing. Further, it introduces the collection of papers for the special themed feature. Five papers look at affective practices through a Continental European lens, which places the meaning of race, migration and intersecting identity angles at the centre of debates of individual encounters in public spaces. The final and sixth paper, written by Brenda Yeoh, looks through a Singapore/East Asia lens, and comments on the common European threats as well as on the historical specificity and implications of distinctive geo-political spaces for affective practices.