Location-Awareness for Radios and Networks: Part I

The papers in this special issue focus on the topic of location awareness for radio and networks. Localization-awareness using radio signals stands to revolutionize the fields of navigation and communication engineering. It can be utilized to great effect in the next generation of cellular networks, mining applications, health-care monitoring, transportation and intelligent highways, multi-robot applications, first responders operations, military applications, factory automation, building and environmental controls, cognitive wireless networks, commercial and social network applications, and smart spaces. A multitude of technologies can be used in location-aware radios and networks, including GNSS, RFID, cellular, UWB, WLAN, Bluetooth, cooperative localization, indoor GPS, device-free localization, IR, Radar, and UHF. The performances of these technologies are measured by their accuracy, precision, complexity, robustness, scalability, and cost. Given the many application scenarios across different disciplines, there is a clear need for a broad, up-to-date and cogent treatment of radio-based location awareness. This special issue aims to provide a comprehensive overview of the state-of-the-art in technology, regulation, and theory. It also presents a holistic view of research challenges and opportunities in the emerging areas of localization.

Non-parametric bill of quantities estimation of concrete road bridges' superstructure: an artificial neural networks approach

Bridge construction responds to the need for environmentally friendly design of motorways and facilitates the passage through sensitive natural areas and the bypassing of urban areas. However, according to numerous research studies, bridge construction presents substantial budget overruns. Therefore, it is necessary early in the planning process for the decision makers to have reliable estimates of the final cost based on previously constructed projects. At the same time, the current European financial crisis reduces the available capital for investments and financial institutions are even less willing to finance transportation infrastructure. Consequently, it is even more necessary today to estimate the budget of high-cost construction projects -such as road bridges- with reasonable accuracy, in order for the state funds to be invested with lower risk and the projects to be designed with the highest possible efficiency. In this paper, a Bill-of-Quantities (BoQ) estimation tool for road bridges is developed in order to support the decisions made at the preliminary planning and design stages of highways. Specifically, a Feed-Forward Artificial Neural Network (ANN) with a hidden layer of 10 neurons is trained to predict the superstructure material quantities (concrete, pre-stressed steel and reinforcing steel) using the width of the deck, the adjusted length of span or cantilever and the type of the bridge as input variables. The training dataset includes actual data from 68 recently constructed concrete motorway bridges in Greece. According to the relevant metrics, the developed model captures very well the complex interrelations in the dataset and demonstrates strong generalisation capability. Furthermore, it outperforms the linear regression models developed for the same dataset. Therefore, the proposed cost estimation model stands as a useful and reliable tool for the construction industry as it enables planners to reach informed decisions for technical and economic planning of concrete bridge projects from their early implementation stages.

Impacts of culling and exclusion of browsers on vegetation recovery across New Zealand forests

Introduced browsing animals negatively impact New Zealand's indigenous ecosystems. Eradicating introduced browsers is currently unfeasible at large scales, but culling since the 1960s has successfully reduced populations to a fraction of their earlier sizes. Here we ask whether culling of ungulates has allowed populations of woody plant species to recover across New Zealand forests. Using 73 pairs of permanent fenced exclosure and unfenced control plots, we found rapid increases in sapling densities within exclosures located in disturbed forests, particularly if a seedling bank was already present. Recovery was slower in thinning stands and hampered by dense fern cover. We inferred ungulate diet preference from species recovery rates inside exclosures to test whether culling increased abundance of preferred species across a national network of 574 unfenced permanent forest plots. Across this network, saplings were observed irrespective of their preference to ungulates in the 1970s, but preferred species were rarer within disturbed sites in the 1990s after long-term culling and despite nationwide increases in sapling densities. This indicates that preferred species are relatively heavily affected by browsing after culling, presumably because remaining animals will increase consumption of preferred species as competition is reduced. Our results clearly suggest that culling will not return preferred plants to the landscape immediately, even given suitable conditions for regeneration. Complete removal of ungulates rather than simply reducing their densities may be required for recovery in heavily browsed temperate forests, but since this is only feasible at small spatial scales, management efforts must target sites of high conservation value. © 2012 Elsevier Ltd.

Lost in Transition? Emerging forms of residential architecture in Kathmandu

Kathmandu has been the last few cities in the world which retained its medieval urban culture up until twentieth century. Various Hindu and Buddhist religious practices shaped the arrangement of houses, roads and urban spaces giving the city a distinctive physical form, character and a unique oriental nativeness. In recent decades, the urban culture of the city has been changing with the forces of urbanisation and globalisation and the demand for new buildings and spaces. New residential design is increasingly dominated by distinctive patterns of Western suburban ideal comprising detached or semi-detached homes and high rise tower blocks. This architectural iconoclasm can be construed as a rather crude response to the indigenous spaces and builtform. The paper attempts to dismantle the current tension between traditional and contemporary 'culture' (and hence society) and housing (or builtform) in Kathmandu by engaging in a discussion that cuts across space, time and meaning of building. The paper concludes that residential architecture in Kathmandu today stands disoriented and lost in the transition.

Operators for Similarity Search: Semantics, Techniques and Usage Scenarios

This book provides a comprehensive tutorial on similarity operators. The authors systematically survey the set of similarity operators, primarily focusing on their semantics, while also touching upon mechanisms for processing them effectively.

The book starts off by providing introductory material on similarity search systems, highlighting the central role of similarity operators in such systems. This is followed by a systematic categorized overview of the variety of similarity operators that have been proposed in literature over the last two decades, including advanced operators such as RkNN, Reverse k-Ranks, Skyline k-Groups and K-N-Match. Since indexing is a core technology in the practical implementation of similarity operators, various indexing mechanisms are summarized. Finally, current research challenges are outlined, so as to enable interested readers to identify potential directions for future investigations.

In summary, this book offers a comprehensive overview of the field of similarity search operators, allowing readers to understand the area of similarity operators as it stands today, and in addition providing them with the background needed to understand recent novel approaches.

In the Shadows of the Old Town: Thomas Anna and 19th-century Glasgow

In 1858, a volume entitled Midnight Scenes and Social Photographs – being sketches of life in the streets, wynds and dens of the city of Glasgow was published under the pseudonym of ‘Shadow’ by Alexander Brown, a Glaswegian flâneur and reformer. Its frontispiece is an etching which depicts a theatre-like proscenium arch whose curtains have been withdrawn to reveal to the audience all the poverty, destitution and disorder that one was likely to find after dark in the insalubrious quarters of the city. At the extreme left-hand side, partly obscured by the curtain a silhouetted figure stands behind an unwieldy camera perched on a tripod. Distinctly unaffected by the mêlée, an arm is calmly raised and a finger precisely arched in the moment before the shutter is clicked and the scene committed to record. The volume, however, relies exclusively on textual descriptions to evoke the underside of the city and contains no photographs at all. Instead, the use of the word photograph in the title can be understood as a metaphor for detached scientific objectivity, a quality much celebrated by nineteenth-century reformers and investigators of social ills. As it happened, a decade after Shadow disappeared into the labyrinthine back-lands of Old Town Glasgow, he was followed there by a real photographer. In 1868, Thomas Annan was commissioned by the City Improvements Trust to take photographs of the Old Town in its last moments of existence before it was pulled down under a series of legislative acts. But perhaps paradoxically, given Shadow’s faith in the analytical properties of photography, Annan’s work seems to refute much of the material contained in Midnight Scenes and other similar tracts. Instead of the dens, shebeens, labyrinths and rowdy crowds described by Shadow, Annan’s depictions of the Old Town convey a static, calm environment, one which is often sparsely inhabited by a curious but apparently orderly population.

Taking account of the sensational tendencies of many reformists’ texts, this paper investigates the discrepancies between the two representations, focussing in particular on the constraints which operated on Annan during his commission. It argues that Annan’s compositions – which became very influential on other 19th century photographers of everyday life such as John Thomson or Jacob Riis – far from being dispassionate analytical works, emerged as a result of a matrix of factors which included: photographic and artistic precedents; Annan’s own predilections as a photographer; technological limitations; the nature of the commission from the City Improvements Trust and political climate in which it was given; the medieval urban fabric in which he had to operate; and, perhaps, most importantly, the identity of the Old Towns inhabitants themselves.

Soil microbes and community coalescence

Community coalescence is a recently introduced term describing the interaction of entire communities and their environments. We here explicitly place the concept of community coalescence in a soil microbial context, exploring intrinsic and extrinsic drivers of such coalescence events. Examples of intrinsic events include the action of earthworms and the dynamics of soil aggregates, while extrinsic events are exemplified by tillage, flooding, litter-fall, outplanting, and the addition of materials containing microbial communities. Aspects of global change may alter the frequency or severity of coalescence events. We highlight functional consequences of community coalescence in soil, and suggest ways to experimentally tackle this phenomenon. Soil ecology as a whole stands to benefit from conceptualizing soil biodiversity in terms of dynamic coalescent microbial assemblages.