33,344 research outputs found

    Multi modal multi-semantic image retrieval

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    PhDThe rapid growth in the volume of visual information, e.g. image, and video can overwhelm users’ ability to find and access the specific visual information of interest to them. In recent years, ontology knowledge-based (KB) image information retrieval techniques have been adopted into in order to attempt to extract knowledge from these images, enhancing the retrieval performance. A KB framework is presented to promote semi-automatic annotation and semantic image retrieval using multimodal cues (visual features and text captions). In addition, a hierarchical structure for the KB allows metadata to be shared that supports multi-semantics (polysemy) for concepts. The framework builds up an effective knowledge base pertaining to a domain specific image collection, e.g. sports, and is able to disambiguate and assign high level semantics to ‘unannotated’ images. Local feature analysis of visual content, namely using Scale Invariant Feature Transform (SIFT) descriptors, have been deployed in the ‘Bag of Visual Words’ model (BVW) as an effective method to represent visual content information and to enhance its classification and retrieval. Local features are more useful than global features, e.g. colour, shape or texture, as they are invariant to image scale, orientation and camera angle. An innovative approach is proposed for the representation, annotation and retrieval of visual content using a hybrid technique based upon the use of an unstructured visual word and upon a (structured) hierarchical ontology KB model. The structural model facilitates the disambiguation of unstructured visual words and a more effective classification of visual content, compared to a vector space model, through exploiting local conceptual structures and their relationships. The key contributions of this framework in using local features for image representation include: first, a method to generate visual words using the semantic local adaptive clustering (SLAC) algorithm which takes term weight and spatial locations of keypoints into account. Consequently, the semantic information is preserved. Second a technique is used to detect the domain specific ‘non-informative visual words’ which are ineffective at representing the content of visual data and degrade its categorisation ability. Third, a method to combine an ontology model with xi a visual word model to resolve synonym (visual heterogeneity) and polysemy problems, is proposed. The experimental results show that this approach can discover semantically meaningful visual content descriptions and recognise specific events, e.g., sports events, depicted in images efficiently. Since discovering the semantics of an image is an extremely challenging problem, one promising approach to enhance visual content interpretation is to use any associated textual information that accompanies an image, as a cue to predict the meaning of an image, by transforming this textual information into a structured annotation for an image e.g. using XML, RDF, OWL or MPEG-7. Although, text and image are distinct types of information representation and modality, there are some strong, invariant, implicit, connections between images and any accompanying text information. Semantic analysis of image captions can be used by image retrieval systems to retrieve selected images more precisely. To do this, a Natural Language Processing (NLP) is exploited firstly in order to extract concepts from image captions. Next, an ontology-based knowledge model is deployed in order to resolve natural language ambiguities. To deal with the accompanying text information, two methods to extract knowledge from textual information have been proposed. First, metadata can be extracted automatically from text captions and restructured with respect to a semantic model. Second, the use of LSI in relation to a domain-specific ontology-based knowledge model enables the combined framework to tolerate ambiguities and variations (incompleteness) of metadata. The use of the ontology-based knowledge model allows the system to find indirectly relevant concepts in image captions and thus leverage these to represent the semantics of images at a higher level. Experimental results show that the proposed framework significantly enhances image retrieval and leads to narrowing of the semantic gap between lower level machinederived and higher level human-understandable conceptualisation

    Unveiling connectivity patterns of categories in complex systems: an application to human needs in urban places

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of mathematical sociology on 06/09/2016, available online: http://www.tandfonline.com/doi/full/10.1080/0022250X.2016.1219855We present a methodology based on weighted networks and dependence coefficients aimed at revealing connectivity patterns between categories. As a case study, it is applied to an urban place and at two spatial levels—neighborhood and square—where categories correspond to human needs. Our results show that diverse spatial levels present different and nontrivial patterns of need emergence. A numerical model indicates that these patterns depend on the probability distribution of weights. We suggest that this way of analyzing the connectivity of categories (human needs in our case study) in social and ecological systems can be used to define new strategies to cope with complex processes, such as those related to transition management and governance, urban-making, and integrated planning.Peer ReviewedPostprint (author's final draft

    The ubiquity of state fragility : fault lines in the categorisation and conceptualisation of failed and fragile states

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    In the last three decades, the categories of fragile and failed states have gained significant importance in the fields of law, development, political science and international relations. The wider discourse plays a key role in guiding the policies of international community and multilateral institutions and has also led to the emergence of a plethora of indices and rankings to measure and classify state fragility. A critical and theoretical analysis of these matrices brings to light three crucial aspects that the current study takes as its departure point. First, the formulas and conceptual paradigms show that fragility of states is far more ubiquitous than is generally recognised, and that the so-called successful and stable states are a historical, political and geographical anomaly. Second, in the absence of an agreed definition of a successful state or even that of a failed or fragile state, the indicators generally rely on negative definitions to delineate the failed and fragile state. They generally suggest that their reading is built on a Weberian ideal–typical state, which takes the idea of monopoly over legitimate violence as its starting point. The third and final point suggests that the indicators and rankings, misconstruing the Weberian ideal–typical state, actually end up comparing fragile states against an ideal–mythical state. The article argues that this notional state is not only ahistorical and apolitical, but it also carries the same undertones that have been the hallmark of theories of linear development, colonialism and imperialism

    Methodology for environmental assessment of agri-environment schemes: the Agri Environmental Footprint Index

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    End of project reportAgri-environment schemes pay farmers for the provision of environmental services. Such schemes tend to have multiple measures that deliver multiple environmental objectives, and there is a lack of consistent methodology with which to measure the environmental benefits of such schemes. Funded by EU FP6, the Agri-Environment Footprint project (www.footprint.rdg.ac.uk) aimed to address this challenge, and this report provides results from selected components of the project.European Unio

    Fund of hedge funds: origins, role and future.

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    The emergence of the fund of hedge funds (FoHF) was the natural evolutionary outcome of the appearance of the hedge fund itself and its consequential rapid rise to success as a result of offering absolute returns to a market where the generality of world savings was invested in relative returns. However, the lack of transparency, large minimum required investment and some early highly publicised accidents restricted access to this investment class mainly to high net worth individuals. To overcome this, the concept of packaging hedge funds into funds of hedge funds was born, though at fi rst with mainly institutional investors using these funds as providers of ill-defi ned alpha rather than introducing them into their portfolios as a particular style. From this simple beginning, the role of the fund of hedge funds has evolved into today’s fully-fledged multi-manager. This progression occurred naturally as the growing concern to identify more rigorously the type of risk from which hedge funds generated their returns and the need for managers to prove their added value meant that, increasingly, funds of hedge funds had to clarify their role in terms of risk management, asset allocation and reporting as they do today. A lack of experience, together with the complexity of risks to which hedge funds were exposed, highlighted both the importance of making a risk assessment prior to an investment, and the importance of risk management during the investment’s lifetime. Despite a better understanding of risk exposures and alpha sources, building a well-diversified multi-manager portfolio remains a diffi cult task. However, due to their in-depth knowledge of alternative styles and their use of an investment process combining top-down asset allocation and bottom-up manager selection, funds of hedge funds have been able to build robust portfolios, generating absolute returns over the long term. Furthermore, capitalising on their ability to consolidate and interpret information from various hedge fund managers has allowed funds of hedge funds to produce meaningful reports for their investors. Over the last few years, it has been thought that the huge infl ow of money into this universe would exhaust the source of alpha. However, this capacity constraint concern has since faded (to be replaced to a certain degree by manager constraints) and funds of hedge funds have been able to strengthen their role by providing secured access to a diversifi ed source of alpha as a result of their ability to identify, monitor and time risk factors. The knowledge acquired in understanding and evaluating the role of skills in producing absolute returns has also proved to be of value when applied to the traditional space, and has contributed to broadening the added value of the managers’ institutional proposition. As funds of hedge funds have become fully-fledged multi-managers in their own right, they are also now able to compete in the institutional sector with the traditional multi-manager.

    Regional development of districts in the Lesser Poland Voivodship

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    Purpose of the article: Regional development includes qualitative changes in economy (e.g. in production, investments, employment) as well as qualitative changes (regarding the structure of economy and society, changes in the environment). The research of regional development is important and necessary in order to make appropriate decisions at the regional and local level. The main purpose of the article is comparative analysis of districts in the Lesser Poland Voivodship in the area of economic, social and ecological development. Scientific aim: The scientific aims of paper are verifying the hypothesis concerning eco-development and forecasting the level of regional development in districts of Lesser Poland Voivodship. Methodology/methods: In the research of regional development the quality index of economic, social and ecological development has been proposed which has been calculated on the basis of a certain aggregation of the results of the Principal Component Analysis made on the correlation matrix of standardised variables being the components of the index. Forecasts of the regional development level in districts were calculated with the use of different econometric models as linear model, exponential model, or power model. Findings: The findings prove that the Lesser Poland Voivodship is characterised by considerable disproportions in regional development. The most favourable conditions for economic and social development are in the districts with large city agglomerations as well as extensive municipality infrastructure and transport infrastructure. The presented results demonstrate that the majority of districts have not exhibited a constant tendency to changes in the positions in successive ranking lists in terms of the economic, social and ecological development. The positions occupied by most districts are generally stable and have not changed considerably in the examined period. Conclusions: The research has confirmed the negative interdependence between the level of socioeconomic development and ecological development. Thus, it was not possible to verify positively the concept of eco-development expressed in keeping balance between the economic, social and ecological system

    The cyclical behaviour of sector and regional diversification benefits: 1987-2002

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    This paper investigates the time series behaviour of the relative benefits of sector and regional diversification strategies, using the notion of cross-sectional dispersion introduced by Solnik and Roulet (2000). Using monthly data over the period 1987:1 to 2002:12, four sector and four regional classifications are examined in the UK. The results indicate that sector and regional dispersion indices are highly time varying and so dwarf any lower frequency cyclical components that may be present. Nonetheless, periods of high dispersion are closely followed by periods of low dispersion, suggestive of cyclical behaviour of sector and regional diversification benefits. Then, using the HP-filter we isolated the cyclical component of the various dispersion indices and found that the sector dispersion indices are generally above the regional dispersion indices. This implies that a sector diversification strategy is likely to offer greater risk reduction benefits than a regional diversification approach. Nonetheless, we find that in some periods, certain regional diversification strategies are of equal or greater benefit than certain sector approaches. The results also appear to be quite sensitive to the classifications of sectors and regions. Hence, the appropriate definition of sectors and regions can have important implications for sector and regional diversification strategies

    Cities and energy:urban morphology and residential heat-energy demand

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    Our aim is better understanding of the theoretical heat-energy demand of different types of urban form at a scale of 500 m × 500 m. The empirical basis of this study includes samples of dominant residential building typologies identified for Paris, London, Berlin, and Istanbul. In addition, archetypal idealised samples were created for each type through an analysis of their built form parameters and the removal of unwanted ‘invasive’ morphologies. The digital elevation models of these real and idealised samples were run through a simulation that modelled solar gains and building surface energy losses to estimate heat-energy demand. In addition to investigating the effect of macroscale morphological parameters, microscale design parameters, such as U-values and glazing ratios, as well as climatic effects were analysed. The theoretical results of this study suggest that urban-morphology-induced heat-energy efficiency is significant and can lead to a difference in heat-energy demand of up to a factor of six. Compact and tall building types were found to have the greatest heat-energy efficiency at the neighbourhood scale while detached housing was found to have the lowest

    Scientific knowledge and scientific uncertainty in bushfire and flood risk mitigation: literature review

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    EXECUTIVE SUMMARY The Scientific Diversity, Scientific Uncertainty and Risk Mitigation Policy and Planning (RMPP) project aims to investigate the diversity and uncertainty of bushfire and flood science, and its contribution to risk mitigation policy and planning. The project investigates how policy makers, practitioners, courts, inquiries and the community differentiate, understand and use scientific knowledge in relation to bushfire and flood risk. It uses qualitative social science methods and case studies to analyse how diverse types of knowledge are ordered and judged as salient, credible and authoritative, and the pragmatic meaning this holds for emergency management across the PPRR spectrum. This research report is the second literature review of the RMPP project and was written before any of the case studies had been completed. It synthesises approximately 250 academic sources on bushfire and flood risk science, including research on hazard modelling, prescribed burning, hydrological engineering, development planning, meteorology, climatology and evacuation planning. The report also incorporates theoretical insights from the fields of risk studies and science and technology studies (STS), as well as indicative research regarding the public understandings of science, risk communication and deliberative planning. This report outlines the key scientific practices (methods and knowledge) and scientific uncertainties in bushfire and flood risk mitigation in Australia. Scientific uncertainties are those ‘known unknowns’ and ‘unknown unknowns’ that emerge from the development and utilisation of scientific knowledge. Risk mitigation involves those processes through which agencies attempt to limit the vulnerability of assets and values to a given hazard. The focus of this report is the uncertainties encountered and managed by risk mitigation professionals in regards to these two hazards, though literature regarding natural sciences and the scientific method more generally are also included where appropriate. It is important to note that while this report excludes professional experience and local knowledge from its consideration of uncertainties and knowledge, these are also very important aspects of risk mitigation which will be addressed in the RMPP project’s case studies. Key findings of this report include: Risk and scientific knowledge are both constructed categories, indicating that attempts to understand any individual instance of risk or scientific knowledge should be understood in light of the social, political, economic, and ecological context in which they emerge. Uncertainty is a necessary element of scientific methods, and as such risk mitigation practitioners and researchers alike should seek to ‘embrace uncertainty’ (Moore et al., 2005) as part of navigating bushfire and flood risk mitigation
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