665 research outputs found
Enhancing Exploratory Analysis across Multiple Levels of Detail of Spatiotemporal Events
Crimes, forest fires, accidents, infectious diseases, human interactions with mobile devices (e.g., tweets) are being logged as spatiotemporal events. For each event, its spatial location, time and related attributes are known with high levels of detail (LoDs). The LoD of analysis plays a crucial role in the user’s perception of phenomena. From one LoD to another, some patterns can be easily perceived or different patterns may be detected, thus requiring modeling phenomena at different LoDs as there is no exclusive LoD to study them.
Granular computing emerged as a paradigm of knowledge representation and processing, where granules are basic ingredients of information. These can be arranged in a hierarchical alike structure, allowing the same phenomenon to be perceived at different LoDs. This PhD Thesis introduces a formal Theory of Granularities (ToG) in order to have granules defined over any domain and reason over them. This approach is more general than the related literature because these appear as particular cases of the proposed ToG. Based on this theory we propose a granular computing approach to model spatiotemporal phenomena at multiple LoDs, and called it a granularities-based model.
This approach stands out from the related literature because it models a phenomenon
through statements rather than just using granules to model abstract real-world entities.
Furthermore, it formalizes the concept of LoD and follows an automated approach to
generalize a phenomenon from one LoD to a coarser one.
Present-day practices work on a single LoD driven by the users despite the fact that
the identification of the suitable LoDs is a key issue for them. This PhD Thesis presents a framework for SUmmarizIng spatioTemporal Events (SUITE) across multiple LoDs. The SUITE framework makes no assumptions about the phenomenon and the analytical task.
A Visual Analytics approach implementing the SUITE framework is presented, which
allow users to inspect a phenomenon across multiple LoDs, simultaneously, thus helping to understand in what LoDs the phenomenon perception is different or in what LoDs patterns emerge
Every Moment Counts: Dense Detailed Labeling of Actions in Complex Videos
Every moment counts in action recognition. A comprehensive understanding of
human activity in video requires labeling every frame according to the actions
occurring, placing multiple labels densely over a video sequence. To study this
problem we extend the existing THUMOS dataset and introduce MultiTHUMOS, a new
dataset of dense labels over unconstrained internet videos. Modeling multiple,
dense labels benefits from temporal relations within and across classes. We
define a novel variant of long short-term memory (LSTM) deep networks for
modeling these temporal relations via multiple input and output connections. We
show that this model improves action labeling accuracy and further enables
deeper understanding tasks ranging from structured retrieval to action
prediction.Comment: To appear in IJC
08451 Abstracts Collection -- Representation, Analysis and Visualization of Moving Objects
From 02.11. to 07.11.2008, the Dagstuhl Seminar 08451 ``Representation, Analysis and Visualization of Moving Objects \u27\u27 was held
in Schloss Dagstuhl~--~Leibniz Center for Informatics.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
A Spatio-Temporal Framework for Managing Archeological Data
Space and time are two important characteristics of data in many domains. This is particularly true in the archaeological context where informa- tion concerning the discovery location of objects allows one to derive important relations between findings of a specific survey or even of different surveys, and time aspects extend from the excavation time, to the dating of archaeological objects. In recent years, several attempts have been performed to develop a spatio-temporal information system tailored for archaeological data. The first aim of this paper is to propose a model, called Star, for repre- senting spatio-temporal data in archaeology. In particular, since in this domain dates are often subjective, estimated and imprecise, Star has to incorporate such vague representation by using fuzzy dates and fuzzy relationships among them. Moreover, besides to the topological relations, another kind of spatial relations is particularly useful in archeology: the stratigraphic ones. There- fore, this paper defines a set of rules for deriving temporal knowledge from the topological and stratigraphic relations existing between two findings. Finally, considering the process through which objects are usually manually dated by archeologists, some existing automatic reasoning techniques may be success- fully applied to guide such process. For this purpose, the last contribution regards the translation of archaeological temporal data into a Fuzzy Temporal Constraint Network for checking the overall data consistency and reducing the vagueness of some dates based on their relationships with other ones
10491 Abstracts Collection -- Representation, Analysis and Visualization of Moving Objects
From December 5 to December 10, 2010, the Dagstuhl Seminar 10491
``Representation, Analysis and Visualization of Moving Objects\u27\u27 was held
in Schloss Dagstuhl~--~Leibniz Center for Informatics.
The major goal of this seminar has been to bring together the diverse and fast
growing, research community that is involved in developing better computational
techniques for spatio-temporal object representation, data mining, and
visualization massive amounts of moving object data.
The participants included experts from fields such as computational geometry, data mining, visual analytics, GIS science, transportation science, urban planning and movement ecology. Most of the participants came from academic institutions, some from government agencies and industry. The seminar has led to a fruitful exchange of ideas between different disciplines, to the creation of new interdisciplinary collaborations, concrete plans for a data challenge in an upcoming conference, and to recommendations for future research directions.
Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper
A Study of Colloquial Place Names through Geotagged Social Media Data
Place is a rich but vague geographic concept. Much work has been done to explore the collective understanding and perceived location of place. The last few decades have seen rapid expansion in the use of online social media and data sharing services, which provide a large amount of valuable data for research of colloquial place names. This study explored how geotagged social media data can be used to understand geographic place names, and delimit the perceived geographic extent of a place. The author proposes a probabilistic method to map the perceived geographic extent of a place using Kernel Density Estimation (KDE) based on the geotagged data uploaded by users. The author also used spatio-temporal analysis methods in GIS to explore characteristics, hidden patterns, and trends of the places. Flickr, a popular online social networking service that features image hosting and sharing, was selected as the main data source for this project. The results show that outcomes of KDE with different functions and parameters differ from each other; therefore, it is crucial to select the proper KDE bandwidth in order to obtain appropriate geographic extents. Official boundaries and reference boundaries can be used to assess the geographic extents. Google Maps Street View is another useful source to examine the visual characteristics of places. Spatio-temporal analysis of the geographic extents over time reveals significant location changes of the places composed of man-made structures. Besides names and variations of place names, related colloquial terms, like Cades Cove of the Great Smoky Mountains National Park, are also useful sources when delimiting a place. Several examples are analyzed and discussed. Studies like this research can improve our understanding of geotagged Online Social Network (OSN) data in the study of colloquial place names as well as provide a temporal perspective to the analysis of their perceived geographic extents
A survey of qualitative spatial representations
Representation and reasoning with qualitative spatial relations is an important problem in artificial intelligence and has wide applications in the fields of geographic information system, computer vision, autonomous robot navigation, natural language understanding, spatial databases and so on. The reasons for this interest in using qualitative spatial relations include cognitive comprehensibility, efficiency and computational facility. This paper summarizes progress in qualitative spatial representation by describing key calculi representing different types of spatial relationships. The paper concludes with a discussion of current research and glimpse of future work
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