232,397 research outputs found
SenseCam image localisation using hierarchical SURF trees
The SenseCam is a wearable camera that automatically takes photos of the wearer's activities, generating thousands of images per day.
Automatically organising these images for efficient search and retrieval is a challenging task, but can be simplified by providing
semantic information with each photo, such as the wearer's location during capture time. We propose a method for automatically determining the wearer's location using an annotated image database, described using SURF interest point descriptors. We show that SURF out-performs SIFT in matching SenseCam images and that matching can be done efficiently using hierarchical trees of SURF descriptors. Additionally, by re-ranking the top images using bi-directional SURF matches, location matching performance is improved further
HySIM: A Hybrid Spectrum and Information Market for TV White Space Networks
We propose a hybrid spectrum and information market for a database-assisted
TV white space network, where the geo-location database serves as both a
spectrum market platform and an information market platform. We study the
inter- actions among the database operator, the spectrum licensee, and
unlicensed users systematically, using a three-layer hierarchical model. In
Layer I, the database and the licensee negotiate the commission fee that the
licensee pays for using the spectrum market platform. In Layer II, the database
and the licensee compete for selling information or channels to unlicensed
users. In Layer III, unlicensed users determine whether they should buy the
exclusive usage right of licensed channels from the licensee, or the
information regarding unlicensed channels from the database. Analyzing such a
three-layer model is challenging due to the co-existence of both positive and
negative network externalities in the information market. We characterize how
the network externalities affect the equilibrium behaviours of all parties
involved. Our numerical results show that the proposed hybrid market can
improve the network profit up to 87%, compared with a pure information market.
Meanwhile, the achieved network profit is very close to the coordinated
benchmark solution (the gap is less than 4% in our simulation).Comment: This manuscript serves as the online technical report of the article
published in IEEE International Conference on Computer Communications
(INFOCOM), 201
Evaluation of Urban Improvement on the Islands of the Venice Lagoon: A Spatially-Distributed Hedonic-Hierarchical Approach
This paper presents a model for the evaluation of environmental and urban improvements on the islands of the Venetian lagoon. The model simulates the changes in residential real estate values using a value function integrated in a geographical database which provides spatial distributions of values changes. The fairly weak market signals, fragmented demand and strong externalities, and the scarcity of market data available do not permit the use of econometric models for value appraisal. Appropriate hedonic-hierarchical value functions are calibrated on the basis of a set of indicators of the characteristics of the buildings and the location. Some applications of the model are illustrated simulating two scenarios of future interventions which are actually being discussed or realised and involving the island of Murano, Burano and S. Erasmo in the Venice Lagoon. The interventions considered are: subway beyond the lagoon connecting Murano with Venice and the mainland, and the solution of âhigh waterâ problems on Murano, Burano and S. Erasmo.Public work assessment, Property value, Hierarchical analysis
Two Distributed Algorithms for E-ticket Validation Protocols for Mobile Clients
The e-ticket (electronic ticket) validation problem has relevance in mobile computing environment because of the multiple submission of a ticket that is possible due to intermittent disconnections and mobility of hosts. Here, we propose protocols that are not only sensitive to disconnection but also to location. One of the proposed protocols is the variant of the distributed protocol proposed by Pedone (2000) for Internet users. This shows that a distributed protocol for static network can be restructured for distributed computation in a mobile computing environment. We have also proposed another protocol that uses a hierarchical location database of mobile hosts (Pitoura and Samaras, 2001)
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Computerized Inventory of Data on Texas Salt Domes
Based on our preliminary investigations, we have developed a computerized spreadsheet that compiles relevant information for storing chemical wastes in salt domes in Texas. This inventory serves as a convenient source of dome-related data, including location, physical dimensions, dome structure, surrounding strata, resources, and groundwater information. The database is particularly valuable for organizing data, generating lists, and creating tables to compare different domes and their potential uses and resources.
DATABASE
The inventory is stored using System 2000 (S2K), providing users with robust tools for managing the database. With S2K, users can define new databases, modify existing definitions, retrieve and update values, and maintain archival copies with an audit trail of changes.
The structure of the database is hierarchical, comprising data elements and repeating groups. Data elements store numeric or text values, while repeating groups organize related sets of data elements, linking different levels of the database. Output in the form of tables and reports is generated using the "Report Writer" tool.Bureau of Economic Geolog
3D Partition-Based Clustering for Supply Chain Data Management
Supply Chain Management (SCM) is the management of the products and goods flow from its origin point to point of
consumption. During the process of SCM, information and dataset gathered for this application is massive and complex. This is due to its
several processes such as procurement, product development and commercialization, physical distribution, outsourcing and partnerships.
For a practical application, SCM datasets need to be managed and maintained to serve a better service to its three main categories;
distributor, customer and supplier. To manage these datasets, a structure of data constellation is used to accommodate the data into the
spatial database. However, the situation in geospatial database creates few problems, for example the performance of the database
deteriorate especially during the query operation. We strongly believe that a more practical hierarchical tree structure is required for
efficient process of SCM. Besides that, three-dimensional approach is required for the management of SCM datasets since it involve with
the multi-level location such as shop lots and residential apartments. 3D R-Tree has been increasingly used for 3D geospatial database
management due to its simplicity and extendibility. However, it suffers from serious overlaps between nodes. In this paper, we proposed
a partition-based clustering for the construction of a hierarchical tree structure. Several datasets are tested using the proposed method and
the percentage of the overlapping nodes and volume coverage are computed and compared with the original 3D R-Tree and other
practical approaches. The experiments demonstrated in this paper substantiated that the hierarchical structure of the proposed partitionbased
clustering is capable of preserving minimal overlap and coverage. The query performance was tested using 300,000 points of a
SCM dataset and the results are presented in this paper. This paper also discusses the outlook of the structure for future reference
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