7,786 research outputs found
Usability testing for improving interactive geovisualization techniques
Usability describes a product’s fitness for use according to a set of predefined criteria.
Whatever the aim of the product, it should facilitate users’ tasks or enhance their performance
by providing appropriate analysis tools. In both cases, the main interest is to satisfy users in
terms of providing relevant functionality which they find fit for purpose. “Testing usability
means making sure that people can find and work with [a product’s] functions to meet their
needs” (Dumas and Redish, 1999: 4). It is therefore concerned with establishing whether
people can use a product to complete their tasks with ease and at the same time help them
complete their jobs more effectively.
This document describes the findings of a usability study carried out on DecisionSite Map
Interaction Services (Map IS). DecisionSite, a product of Spotfire, Inc.,1 is an interactive
system for the visual and dynamic exploration of data designed for supporting decisionmaking.
The system was coupled to ArcExplorer (forming DecisionSite Map IS) to provide
limited GIS functionality (simple user interface, basic tools, and data management) and
support users of spatial data. Hence, this study set out to test the suitability of the coupling
between the two software components (DecisionSite and ArcExplorer) for the purpose of
exploring spatial data. The first section briefly discusses DecisionSite’s visualization
functionality. The second section describes the test goals, its design, the participants and data
used. The following section concentrates on the analysis of results, while the final section
discusses future areas of research and possible development
Stochastic Attraction-Repulsion Embedding for Large Scale Image Localization
This paper tackles the problem of large-scale image-based localization (IBL)
where the spatial location of a query image is determined by finding out the
most similar reference images in a large database. For solving this problem, a
critical task is to learn discriminative image representation that captures
informative information relevant for localization. We propose a novel
representation learning method having higher location-discriminating power. It
provides the following contributions: 1) we represent a place (location) as a
set of exemplar images depicting the same landmarks and aim to maximize
similarities among intra-place images while minimizing similarities among
inter-place images; 2) we model a similarity measure as a probability
distribution on L_2-metric distances between intra-place and inter-place image
representations; 3) we propose a new Stochastic Attraction and Repulsion
Embedding (SARE) loss function minimizing the KL divergence between the learned
and the actual probability distributions; 4) we give theoretical comparisons
between SARE, triplet ranking and contrastive losses. It provides insights into
why SARE is better by analyzing gradients. Our SARE loss is easy to implement
and pluggable to any CNN. Experiments show that our proposed method improves
the localization performance on standard benchmarks by a large margin.
Demonstrating the broad applicability of our method, we obtained the third
place out of 209 teams in the 2018 Google Landmark Retrieval Challenge. Our
code and model are available at https://github.com/Liumouliu/deepIBL.Comment: ICC
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Application of Advanced Early Warning Systems with Adaptive Protection
This project developed and field-tested two methods of Adaptive Protection systems utilizing synchrophasor data. One method detects conditions of system stress that can lead to unintended relay operation, and initiates a supervisory signal to modify relay response in real time to avoid false trips. The second method detects the possibility of false trips of impedance relays as stable system swings “encroach” on the relays’ impedance zones, and produces an early warning so that relay engineers can re-evaluate relay settings. In addition, real-time synchrophasor data produced by this project was used to develop advanced visualization techniques for display of synchrophasor data to utility operators and engineers
Management of spatial data for visualization on mobile devices
Vector-based mapping is emerging as a preferred format in Location-based
Services(LBS), because it can deliver an up-to-date and interactive map visualization.
The Progressive Transmission(PT) technique has been developed to
enable the ecient transmission of vector data over the internet by delivering
various incremental levels of detail(LoD). However, it is still challenging to apply
this technique in a mobile context due to many inherent limitations of mobile
devices, such as small screen size, slow processors and limited memory. Taking
account of these limitations, PT has been extended by developing a framework of
ecient data management for the visualization of spatial data on mobile devices.
A data generalization framework is proposed and implemented in a software
application. This application can signicantly reduce the volume of data for
transmission and enable quick access to a simplied version of data while preserving
appropriate visualization quality. Using volunteered geographic information
as a case-study, the framework shows
exibility in delivering up-to-date spatial
information from dynamic data sources.
Three models of PT are designed and implemented to transmit the additional
LoD renements: a full scale PT as an inverse of generalisation, a viewdependent
PT, and a heuristic optimised view-dependent PT. These models are
evaluated with user trials and application examples. The heuristic optimised
view-dependent PT has shown a signicant enhancement over the traditional PT
in terms of bandwidth-saving and smoothness of transitions.
A parallel data management strategy associated with three corresponding
algorithms has been developed to handle LoD spatial data on mobile clients.
This strategy enables the map rendering to be performed in parallel with a process
which retrieves the data for the next map location the user will require. A viewdependent
approach has been integrated to monitor the volume of each LoD for
visible area. The demonstration of a
exible rendering style shows its potential
use in visualizing dynamic geoprocessed data. Future work may extend this
to integrate topological constraints and semantic constraints for enhancing the
vector map visualization
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Stacking-based visualization of trajectory attribute data
Visualizing trajectory attribute data is challenging because it involves showing the trajectories in their spatio-temporal context as well as the attribute values associated with the individual points of trajectories. Previous work on trajectory visualization addresses selected aspects of this problem, but not all of them. We present a novel approach to visualizing trajectory attribute data. Our solution covers space, time, and attribute values. Based on an analysis of relevant visualization tasks, we designed the visualization solution around the principle of stacking trajectory bands. The core of our approach is a hybrid 2D/3D display. A 2D map serves as a reference for the spatial context, and the trajectories are visualized as stacked 3D trajectory bands along which attribute values are encoded by color. Time is integrated through appropriate ordering of bands and through a dynamic query mechanism that feeds temporally aggregated information to a circular time display. An additional 2D time graph shows temporal information in full detail by stacking 2D trajectory bands. Our solution is equipped with analytical and interactive mechanisms for selecting and ordering of trajectories, and adjusting the color mapping, as well as coordinated highlighting and dedicated 3D navigation. We demonstrate the usefulness of our novel visualization by three examples related to radiation surveillance, traffic analysis, and maritime navigation. User feedback obtained in a small experiment indicates that our hybrid 2D/3D solution can be operated quite well
MusA: Using Indoor Positioning and Navigation to Enhance Cultural Experiences in a museum
In recent years there has been a growing interest into the use of multimedia mobile guides in museum environments. Mobile devices have the capabilities to detect the user context and to provide pieces of information suitable to help visitors discovering and following the logical and emotional connections that develop during the visit. In this scenario, location based services (LBS) currently represent an asset, and the choice of the technology to determine users' position, combined with the definition of methods that can effectively convey information, become key issues in the design process. In this work, we present MusA (Museum Assistant), a general framework for the development of multimedia interactive guides for mobile devices. Its main feature is a vision-based indoor positioning system that allows the provision of several LBS, from way-finding to the contextualized communication of cultural contents, aimed at providing a meaningful exploration of exhibits according to visitors' personal interest and curiosity. Starting from the thorough description of the system architecture, the article presents the implementation of two mobile guides, developed to respectively address adults and children, and discusses the evaluation of the user experience and the visitors' appreciation of these application
Schematic bus transit maps for the web using genetic algorithms
Dissertation submitted in partial fulfilment of the requirements for the degree of Master of Science in Geospatial TechnologiesThe octilinear schematic map, layout recognized worldwide in metro maps, is an
important transit informative tool. This research investigates how algorithms for the
visualization of schematic maps can be availed in mobile web devices context in
order to empower the efficiency in transmitting information of bus transit maps. A
genetic algorithm for path octilinear schematization technique has been used and
tested to create the schematic data. Location-based and interactivity functionalities
were embedded to the resulting digital maps in order to create personalized maps to
meet specific user needs. A prototype of a web application and real transit data of the
city of CastellĂłn in Spain was used to test the methodology. The results have shown
that real time schematizations open possibilities concerning usability that add extra
value to schematic transit maps. Additionally, suggested improvements have been
made to the genetic algorithm and performance tests show that genetic algorithms are
adequate, in terms of efficiency, to sketch bus transit maps automatically
Constructive 3D Visualization techniques on Mobile platform- Empirical Analysis
As per the concept of 3D visualization on mobile devices it is clear that it belongs to two approaches i.e. local and remote approach. According to the technological advances in mobile devices it is possible to handle some complex data locally and visualized it. But still it is a challenging task to manage real entities on mobile devices locally. Remote visualization plays a vital role for 3D visualization on mobile platform in which data comes from server. Remote approach for 3D visualization on mobile platform consist of various techniques, critical analysis of such techniques is focus into this paper. Also the main focus is on network aspects
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