5,656 research outputs found

    A conceptual framework and a risk management approach for interoperability between geospatial datacubes

    Get PDF
    De nos jours, nous observons un intĂ©rĂȘt grandissant pour les bases de donnĂ©es gĂ©ospatiales multidimensionnelles. Ces bases de donnĂ©es sont dĂ©veloppĂ©es pour faciliter la prise de dĂ©cisions stratĂ©giques des organisations, et plus spĂ©cifiquement lorsqu’il s’agit de donnĂ©es de diffĂ©rentes Ă©poques et de diffĂ©rents niveaux de granularitĂ©. Cependant, les utilisateurs peuvent avoir besoin d’utiliser plusieurs bases de donnĂ©es gĂ©ospatiales multidimensionnelles. Ces bases de donnĂ©es peuvent ĂȘtre sĂ©mantiquement hĂ©tĂ©rogĂšnes et caractĂ©risĂ©es par diffĂ©rent degrĂ©s de pertinence par rapport au contexte d’utilisation. RĂ©soudre les problĂšmes sĂ©mantiques liĂ©s Ă  l’hĂ©tĂ©rogĂ©nĂ©itĂ© et Ă  la diffĂ©rence de pertinence d’une maniĂšre transparente aux utilisateurs a Ă©tĂ© l’objectif principal de l’interopĂ©rabilitĂ© au cours des quinze derniĂšres annĂ©es. Dans ce contexte, diffĂ©rentes solutions ont Ă©tĂ© proposĂ©es pour traiter l’interopĂ©rabilitĂ©. Cependant, ces solutions ont adoptĂ© une approche non systĂ©matique. De plus, aucune solution pour rĂ©soudre des problĂšmes sĂ©mantiques spĂ©cifiques liĂ©s Ă  l’interopĂ©rabilitĂ© entre les bases de donnĂ©es gĂ©ospatiales multidimensionnelles n’a Ă©tĂ© trouvĂ©e. Dans cette thĂšse, nous supposons qu’il est possible de dĂ©finir une approche qui traite ces problĂšmes sĂ©mantiques pour assurer l’interopĂ©rabilitĂ© entre les bases de donnĂ©es gĂ©ospatiales multidimensionnelles. Ainsi, nous dĂ©finissons tout d’abord l’interopĂ©rabilitĂ© entre ces bases de donnĂ©es. Ensuite, nous dĂ©finissons et classifions les problĂšmes d’hĂ©tĂ©rogĂ©nĂ©itĂ© sĂ©mantique qui peuvent se produire au cours d’une telle interopĂ©rabilitĂ© de diffĂ©rentes bases de donnĂ©es gĂ©ospatiales multidimensionnelles. Afin de rĂ©soudre ces problĂšmes d’hĂ©tĂ©rogĂ©nĂ©itĂ© sĂ©mantique, nous proposons un cadre conceptuel qui se base sur la communication humaine. Dans ce cadre, une communication s’établit entre deux agents systĂšme reprĂ©sentant les bases de donnĂ©es gĂ©ospatiales multidimensionnelles impliquĂ©es dans un processus d’interopĂ©rabilitĂ©. Cette communication vise Ă  Ă©changer de l’information sur le contenu de ces bases. Ensuite, dans l’intention d’aider les agents Ă  prendre des dĂ©cisions appropriĂ©es au cours du processus d’interopĂ©rabilitĂ©, nous Ă©valuons un ensemble d’indicateurs de la qualitĂ© externe (fitness-for-use) des schĂ©mas et du contexte de production (ex., les mĂ©tadonnĂ©es). Finalement, nous mettons en Ɠuvre l’approche afin de montrer sa faisabilitĂ©.Today, we observe wide use of geospatial databases that are implemented in many forms (e.g., transactional centralized systems, distributed databases, multidimensional datacubes). Among those possibilities, the multidimensional datacube is more appropriate to support interactive analysis and to guide the organization’s strategic decisions, especially when different epochs and levels of information granularity are involved. However, one may need to use several geospatial multidimensional datacubes which may be semantically heterogeneous and having different degrees of appropriateness to the context of use. Overcoming the semantic problems related to the semantic heterogeneity and to the difference in the appropriateness to the context of use in a manner that is transparent to users has been the principal aim of interoperability for the last fifteen years. However, in spite of successful initiatives, today's solutions have evolved in a non systematic way. Moreover, no solution has been found to address specific semantic problems related to interoperability between geospatial datacubes. In this thesis, we suppose that it is possible to define an approach that addresses these semantic problems to support interoperability between geospatial datacubes. For that, we first describe interoperability between geospatial datacubes. Then, we define and categorize the semantic heterogeneity problems that may occur during the interoperability process of different geospatial datacubes. In order to resolve semantic heterogeneity between geospatial datacubes, we propose a conceptual framework that is essentially based on human communication. In this framework, software agents representing geospatial datacubes involved in the interoperability process communicate together. Such communication aims at exchanging information about the content of geospatial datacubes. Then, in order to help agents to make appropriate decisions during the interoperability process, we evaluate a set of indicators of the external quality (fitness-for-use) of geospatial datacube schemas and of production context (e.g., metadata). Finally, we implement the proposed approach to show its feasibility

    Towards development of fuzzy spatial datacubes : fundamental concepts with example for multidimensional coastal erosion risk assessment and representation

    Get PDF
    Les systĂšmes actuels de base de donnĂ©es gĂ©odĂ©cisionnels (GeoBI) ne tiennent gĂ©nĂ©ralement pas compte de l'incertitude liĂ©e Ă  l'imprĂ©cision et le flou des objets; ils supposent que les objets ont une sĂ©mantique, une gĂ©omĂ©trie et une temporalitĂ© bien dĂ©finies et prĂ©cises. Un exemple de cela est la reprĂ©sentation des zones Ă  risque par des polygones avec des limites bien dĂ©finies. Ces polygones sont crĂ©Ă©s en utilisant des agrĂ©gations d'un ensemble d'unitĂ©s spatiales dĂ©finies sur soit des intĂ©rĂȘts des organismes responsables ou les divisions de recensement national. MalgrĂ© la variation spatio-temporelle des multiples critĂšres impliquĂ©s dans l’analyse du risque, chaque polygone a une valeur unique de risque attribuĂ© de façon homogĂšne sur l'Ă©tendue du territoire. En rĂ©alitĂ©, la valeur du risque change progressivement d'un polygone Ă  l'autre. Le passage d'une zone Ă  l'autre n'est donc pas bien reprĂ©sentĂ© avec les modĂšles d’objets bien dĂ©finis (crisp). Cette thĂšse propose des concepts fondamentaux pour le dĂ©veloppement d'une approche combinant le paradigme GeoBI et le concept flou de considĂ©rer la prĂ©sence de l’incertitude spatiale dans la reprĂ©sentation des zones Ă  risque. En fin de compte, nous supposons cela devrait amĂ©liorer l’analyse du risque. Pour ce faire, un cadre conceptuel est dĂ©veloppĂ© pour crĂ©er un model conceptuel d’une base de donnĂ©e multidimensionnelle avec une application pour l’analyse du risque d’érosion cĂŽtier. Ensuite, une approche de la reprĂ©sentation des risques fondĂ©e sur la logique floue est dĂ©veloppĂ©e pour traiter l'incertitude spatiale inhĂ©rente liĂ©e Ă  l'imprĂ©cision et le flou des objets. Pour cela, les fonctions d'appartenance floues sont dĂ©finies en basant sur l’indice de vulnĂ©rabilitĂ© qui est un composant important du risque. Au lieu de dĂ©terminer les limites bien dĂ©finies entre les zones Ă  risque, l'approche proposĂ©e permet une transition en douceur d'une zone Ă  une autre. Les valeurs d'appartenance de plusieurs indicateurs sont ensuite agrĂ©gĂ©es basĂ©es sur la formule des risques et les rĂšgles SI-ALORS de la logique floue pour reprĂ©senter les zones Ă  risque. Ensuite, les Ă©lĂ©ments clĂ©s d'un cube de donnĂ©es spatiales floues sont formalisĂ©s en combinant la thĂ©orie des ensembles flous et le paradigme de GeoBI. En plus, certains opĂ©rateurs d'agrĂ©gation spatiale floue sont prĂ©sentĂ©s. En rĂ©sumĂ©, la principale contribution de cette thĂšse se rĂ©fĂšre de la combinaison de la thĂ©orie des ensembles flous et le paradigme de GeoBI. Cela permet l’extraction de connaissances plus comprĂ©hensibles et appropriĂ©es avec le raisonnement humain Ă  partir de donnĂ©es spatiales et non-spatiales. Pour ce faire, un cadre conceptuel a Ă©tĂ© proposĂ© sur la base de paradigme GĂ©oBI afin de dĂ©velopper un cube de donnĂ©es spatiale floue dans le system de Spatial Online Analytical Processing (SOLAP) pour Ă©valuer le risque de l'Ă©rosion cĂŽtiĂšre. Cela nĂ©cessite d'abord d'Ă©laborer un cadre pour concevoir le modĂšle conceptuel basĂ© sur les paramĂštres de risque, d'autre part, de mettre en Ɠuvre l’objet spatial flou dans une base de donnĂ©es spatiales multidimensionnelle, puis l'agrĂ©gation des objets spatiaux flous pour envisager Ă  la reprĂ©sentation multi-Ă©chelle des zones Ă  risque. Pour valider l'approche proposĂ©e, elle est appliquĂ©e Ă  la rĂ©gion Perce (Est du QuĂ©bec, Canada) comme une Ă©tude de cas.Current Geospatial Business Intelligence (GeoBI) systems typically do not take into account the uncertainty related to vagueness and fuzziness of objects; they assume that the objects have well-defined and exact semantics, geometry, and temporality. Representation of fuzzy zones by polygons with well-defined boundaries is an example of such approximation. This thesis uses an application in Coastal Erosion Risk Analysis (CERA) to illustrate the problems. CERA polygons are created using aggregations of a set of spatial units defined by either the stakeholders’ interests or national census divisions. Despite spatiotemporal variation of the multiple criteria involved in estimating the extent of coastal erosion risk, each polygon typically has a unique value of risk attributed homogeneously across its spatial extent. In reality, risk value changes gradually within polygons and when going from one polygon to another. Therefore, the transition from one zone to another is not properly represented with crisp object models. The main objective of the present thesis is to develop a new approach combining GeoBI paradigm and fuzzy concept to consider the presence of the spatial uncertainty in the representation of risk zones. Ultimately, we assume this should improve coastal erosion risk assessment. To do so, a comprehensive GeoBI-based conceptual framework is developed with an application for Coastal Erosion Risk Assessment (CERA). Then, a fuzzy-based risk representation approach is developed to handle the inherent spatial uncertainty related to vagueness and fuzziness of objects. Fuzzy membership functions are defined by an expert-based vulnerability index. Instead of determining well-defined boundaries between risk zones, the proposed approach permits a smooth transition from one zone to another. The membership values of multiple indicators (e.g. slop and elevation of region under study, infrastructures, houses, hydrology network and so on) are then aggregated based on risk formula and Fuzzy IF-THEN rules to represent risk zones. Also, the key elements of a fuzzy spatial datacube are formally defined by combining fuzzy set theory and GeoBI paradigm. In this regard, some operators of fuzzy spatial aggregation are also formally defined. The main contribution of this study is combining fuzzy set theory and GeoBI. This makes spatial knowledge discovery more understandable with human reasoning and perception. Hence, an analytical conceptual framework was proposed based on GeoBI paradigm to develop a fuzzy spatial datacube within Spatial Online Analytical Processing (SOLAP) to assess coastal erosion risk. This necessitates developing a framework to design a conceptual model based on risk parameters, implementing fuzzy spatial objects in a spatial multi-dimensional database, and aggregating fuzzy spatial objects to deal with multi-scale representation of risk zones. To validate the proposed approach, it is applied to Perce region (Eastern Quebec, Canada) as a case study

    A Survey of Volunteered Open Geo-Knowledge Bases in the Semantic Web

    Full text link
    Over the past decade, rapid advances in web technologies, coupled with innovative models of spatial data collection and consumption, have generated a robust growth in geo-referenced information, resulting in spatial information overload. Increasing 'geographic intelligence' in traditional text-based information retrieval has become a prominent approach to respond to this issue and to fulfill users' spatial information needs. Numerous efforts in the Semantic Geospatial Web, Volunteered Geographic Information (VGI), and the Linking Open Data initiative have converged in a constellation of open knowledge bases, freely available online. In this article, we survey these open knowledge bases, focusing on their geospatial dimension. Particular attention is devoted to the crucial issue of the quality of geo-knowledge bases, as well as of crowdsourced data. A new knowledge base, the OpenStreetMap Semantic Network, is outlined as our contribution to this area. Research directions in information integration and Geographic Information Retrieval (GIR) are then reviewed, with a critical discussion of their current limitations and future prospects

    2016: Maximizing Customer Convenience with Hill Climbing

    Get PDF
    As technology advances and the pace of life quickens, companies are expected to continually provide better services, be more accessible, and respond to requests faster. While such expectations have led to the rapid growth of retail stores and service locations throughout the United States, delivery services have arguably been the most influenced by these rising demands. Amazon.com is an online storefront that has seen tremendous growth throughout its lifetime, and it only continues to grow. Founded in 1994 as an online bookstore, the digital retailer eventually expanded its services to include technology, home goods, and even eBooks. Amazon’s response to its customer’s rising demands of customers was to grow and evolve. In February of 2005, Amazon launched Amazon Prime, a service that provided express shipping for hundreds of thousands of products. Amazon believed that fast deliveries should not be an occasional indulgence, but an everyday experience [1]. While the company previously advertised a four-to-six day shipping time, Amazon Prime boasts a mere two day shipping time. Prime was so popular with customers that in 2014, the electronic retailer decided to evolve even further, adding Prime Now, a same day delivery option, to its list of services, granting members free two hour delivery. Prime Now, PrimeNow.com, and Amazon’s constant growth makes one wonder, How can Amazon achieve such absurdly short delivery times? A likely answer lies with efficiently distributed warehouses. While it is possible for a delivery service company to operate solely from its headquarters, such centralization would result in inconsistent, sub-optimal delivery times, with times differing between locations nearer and farther away. The solution is to have warehouses scattered throughout the country, ensuring the presence of nearby locations to service any given customer. On the same note, it is important to consider the physical viability of such an option. A warehouse can be expensive to maintain, so the amount and placement of the warehouses must be optimized such that the service requirement can be met while also being cost efficient. Companies like Amazon who can afford to offer free delivery succeeded in balancing coverage area and company costs, and our company, SportsmanSHIP, intends to do the same. SportsmanSHIP is a recreational equipment company based in New Hampshire. Currently, we have a physical location that customers can buy from, but most of our business is conducted through online sales. Due to an increased demand for our products, we have decided to expand our company by opening warehouses across America. Amazon currently has great coverage across the United States, guaranteeing two day shipping for all areas, and two hour shipping for select locations, but we believe that we can do better. We are a team of SportsmanSHIP employees that also share a passion for mathematical modeling, and we have been tasked with optimizing SportsmanSHIP’s warehouse locations. Our warehouse distribution will allow us to provide one day shipping to nearly all of the United States, and we will do so with minimal warehouses. In this paper, we analyze the crux of large delivery service companies: efficient warehouse distribution. We identify important factors of efficiency such as amount of warehouses, population density, and national coverage. Using these factors, along with data given in regional maps, we constructed a comprehensive model for efficient warehouse placement. Our ultimate goal was to lower shipping time below one day for customers across the United States while minimizing the number of warehouses. In addition, we were asked to consider and discuss the implications of state sales tax on the model, as well as to account for taxes on clothing and apparel, which SportsmanSHIP plans on adding to our inventory in the near future. To tackle the task at hand, we implemented a model that used a Markov Chain Monte Carlo (MCMC) algorithm to determine the utility of a sample distribution. For the first task, maximizing Page 2 of 26 Team #7204 national coverage and minimizing number of warehouses, this utility function considered in the percentage of the United Stat;es covered by a one-day warehouse shipping facility as well as the number of warehouses used. For the next task, we extended this model to include a sales tax calculation factor, negatively impacting the utility of a model with a large amounts of sales tax. For the third task, we modified the sales tax factor to include a weighted tax factor that took into account both clothing and sales taxes. Finally, we developed a separate economic model that compares utility based off of profit only, and does not weight the percent of the United States covered nearly as strongly. This was implemented as another way to look at the problem of optimizing warehouses, since it has been found that only 4% of customers truly care about same-day or one-day shipping [10]. Using our models, SportsmanSHIP’s expansion is guaranteed to be a success, and one day, we may even surpass Amazon. All it takes is a bit of warehouse knowledge, and a lot of math

    Peculiarities in the Development of Special Economic Zones and Industrial Parks in Russia

    Get PDF
    open access journalThis paper investigates the process of developing and implementing Special Economic Zones (SEZs) and industrial parks in Russia. Governments commonly use SEZ policies to develop and diversify exports, create jobs, and launch technology and knowledge sharing. The industrial cluster concept is based on the significance of rivalry and supplier networks within the cluster, the combination of geographical specificities and government policies that lead to innovation and productivity growth. This study reveals that, in Russia, the government’s approach in developing these initiatives has strongly interfered with business activities and prevented the vital competitive and collaborative behavior of firms within these economic zones

    The structure of mercantile communities in the Roman world : how open were Roman trade networks?

    Get PDF

    Developing a model and a language to identify and specify the integrity constraints in spatial datacubes

    Get PDF
    La qualité des données dans les cubes de données spatiales est importante étant donné que ces données sont utilisées comme base pour la prise de décision dans les grandes organisations. En effet, une mauvaise qualité de données dans ces cubes pourrait nous conduire à une mauvaise prise de décision. Les contraintes d'intégrité jouent un rÎle clé pour améliorer la cohérence logique de toute base de données, l'un des principaux éléments de la qualité des données. Différents modÚles de cubes de données spatiales ont été proposés ces derniÚres années mais aucun n'inclut explicitement les contraintes d'intégrité. En conséquence, les contraintes d'intégrité de cubes de données spatiales sont traitées de façon non-systématique, pragmatique, ce qui rend inefficace le processus de vérification de la cohérence des données dans les cubes de données spatiales. Cette thÚse fournit un cadre théorique pour identifier les contraintes d'intégrité dans les cubes de données spatiales ainsi qu'un langage formel pour les spécifier. Pour ce faire, nous avons d'abord proposé un modÚle formel pour les cubes de données spatiales qui en décrit les différentes composantes. En nous basant sur ce modÚle, nous avons ensuite identifié et catégorisé les différents types de contraintes d'intégrité dans les cubes de données spatiales. En outre, puisque les cubes de données spatiales contiennent typiquement à la fois des données spatiales et temporelles, nous avons proposé une classification des contraintes d'intégrité des bases de données traitant de l'espace et du temps. Ensuite, nous avons présenté un langage formel pour spécifier les contraintes d'intégrité des cubes de données spatiales. Ce langage est basé sur un langage naturel contrÎlé et hybride avec des pictogrammes. Plusieurs exemples de contraintes d'intégrité des cubes de données spatiales sont définis en utilisant ce langage. Les designers de cubes de données spatiales (analystes) peuvent utiliser le cadre proposé pour identifier les contraintes d'intégrité et les spécifier au stade de la conception des cubes de données spatiales. D'autre part, le langage formel proposé pour spécifier des contraintes d'intégrité est proche de la façon dont les utilisateurs finaux expriment leurs contraintes d'intégrité. Par conséquent, en utilisant ce langage, les utilisateurs finaux peuvent vérifier et valider les contraintes d'intégrité définies par l'analyste au stade de la conception

    Malawi’s Maize Marketing System

    Get PDF
    National food security in Malawi depends on improving the performance of maize markets. Ensuring that grain is consistently available at tolerable prices is crucial for consumers’ food security. At the same time, surplus producing farmers need to receive farm-gate prices consistently above production costs to intensify the use of fertilizer and other productivity enhancing technologies in a sustainable manner. These concerns give rise to the classic food price dilemma for policy makers in Malawi: how to keep prices low enough to ensure low income consumers’ access to food while keeping prices high enough to promote farm production incentives. These tensions cannot be avoided but they can be relieved through reducing food marketing margins, which shrink the wedge between producer and consumer prices. Moreover, Malawi faces major political and economic problems associated with food price instability especially given its dependence on rain fed agriculture in a region prone to drought. These issues show that improving the performance of maize markets is at the core of achieving sustainable food security and poverty reduction in Malawi.food security, Malawi, maize, marketing, food policy, Agricultural and Food Policy, Community/Rural/Urban Development, Food Security and Poverty, International Development, Marketing, q12, q18,
    • 

    corecore