995 research outputs found
Machine Learning Approaches to Maritime Anomaly Detection
Topics related to safety in maritime transport have become very important over the past decades due to numerous maritime problems putting both human lives and the environment in danger. Recent advances in surveillance technology and the need for better sea traffic protection led to development of automated solutions for detecting anomalies. These solutions are based on generating normality models from data gathered on vessel movement, mostly from AIS. This paper provides a presentation of various machine learning approaches for anomaly detection in the maritime domain. It also addresses potential problems and challenges that could get in the way of successful automation of such systems
Context Awareness for Navigation Applications
This thesis examines the topic of context awareness for navigation applications and asks the question, “What are the benefits and constraints of introducing context awareness in navigation?” Context awareness can be defined as a computer’s ability to understand the situation or context in which it is operating. In particular, we are interested in how context awareness can be used to understand the navigation needs of people using mobile computers, such as smartphones, but context awareness can also benefit other types of navigation users, such as maritime navigators. There are countless other potential applications of context awareness, but this thesis focuses on applications related to navigation. For example, if a smartphone-based navigation system can understand when a user is walking, driving a car, or riding a train, then it can adapt its navigation algorithms to improve positioning performance.
We argue that the primary set of tools available for generating context awareness is
machine learning. Machine learning is, in fact, a collection of many different algorithms and techniques for developing “computer systems that automatically improve their performance through experience” [1]. This thesis examines systematically the ability of existing algorithms from machine learning to endow computing systems with context awareness. Specifically, we apply machine learning techniques to tackle three different tasks related to context awareness and having applications in the field of navigation:
(1) to recognize the activity of a smartphone user in an indoor office environment,
(2) to recognize the mode of motion that a smartphone user is undergoing outdoors, and
(3) to determine the optimal path of a ship traveling through ice-covered waters. The
diversity of these tasks was chosen intentionally to demonstrate the breadth of problems encompassed by the topic of context awareness.
During the course of studying context awareness, we adopted two conceptual “frameworks,” which we find useful for the purpose of solidifying the abstract concepts of context and context awareness. The first such framework is based strongly on the writings of a rhetorician from Hellenistic Greece, Hermagoras of Temnos, who defined seven elements of “circumstance”. We adopt these seven elements to describe contextual information. The second framework, which we dub the “context pyramid” describes the processing of raw sensor data into contextual information in terms of six different levels. At the top of the pyramid is “rich context”, where the information is expressed in prose, and the goal for the computer is to mimic the way that a human would describe a situation.
We are still a long way off from computers being able to match a human’s ability to
understand and describe context, but this thesis improves the state-of-the-art in context awareness for navigation applications. For some particular tasks, machine learning has succeeded in outperforming humans, and in the future there are likely to be tasks in navigation where computers outperform humans. One example might be the route optimization task described above. This is an example of a task where many different types of information must be fused in non-obvious ways, and it may be that computer algorithms can find better routes through ice-covered waters than even well-trained human navigators. This thesis provides only preliminary evidence of this possibility, and future work is needed to further develop the techniques outlined here. The same can be said of the other two navigation-related tasks examined in this thesis
Proceedings of the 2011 Joint Workshop of Fraunhofer IOSB and Institute for Anthropomatics, Vision and Fusion Laboratory
This book is a collection of 15 reviewed technical reports summarizing the presentations at the 2011 Joint Workshop of Fraunhofer IOSB and Institute for Anthropomatics, Vision and Fusion Laboratory. The covered topics include image processing, optical signal processing, visual inspection, pattern recognition and classification, human-machine interaction, world and situation modeling, autonomous system localization and mapping, information fusion, and trust propagation in sensor networks
Automatic human behaviour anomaly detection in surveillance video
This thesis work focusses upon developing the capability to automatically evaluate
and detect anomalies in human behaviour from surveillance video. We work with
static monocular cameras in crowded urban surveillance scenarios, particularly air-
ports and commercial shopping areas. Typically a person is 100 to 200 pixels high
in a scene ranging from 10 - 20 meters width and depth, populated by 5 to 40 peo-
ple at any given time. Our procedure evaluates human behaviour unobtrusively to
determine outlying behavioural events,
agging abnormal events to the operator.
In order to achieve automatic human behaviour anomaly detection we address
the challenge of interpreting behaviour within the context of the social and physical
environment. We develop and evaluate a process for measuring social connectivity
between individuals in a scene using motion and visual attention features. To do this
we use mutual information and Euclidean distance to build a social similarity matrix
which encodes the social connection strength between any two individuals. We de-
velop a second contextual basis which acts by segmenting a surveillance environment
into behaviourally homogeneous subregions which represent high tra c slow regions
and queuing areas. We model the heterogeneous scene in homogeneous subgroups
using both contextual elements. We bring the social contextual information, the
scene context, the motion, and visual attention features together to demonstrate
a novel human behaviour anomaly detection process which nds outlier behaviour
from a short sequence of video. The method, Nearest Neighbour Ranked Outlier
Clusters (NN-RCO), is based upon modelling behaviour as a time independent se-
quence of behaviour events, can be trained in advance or set upon a single sequence.
We nd that in a crowded scene the application of Mutual Information-based social
context permits the ability to prevent self-justifying groups and propagate anomalies
in a social network, granting a greater anomaly detection capability. Scene context
uniformly improves the detection of anomalies in all the datasets we test upon.
We additionally demonstrate that our work is applicable to other data domains.
We demonstrate upon the Automatic Identi cation Signal data in the maritime
domain. Our work is capable of identifying abnormal shipping behaviour using joint
motion dependency as analogous for social connectivity, and similarly segmenting
the shipping environment into homogeneous regions
Machine learning in marine ecology: an overview of techniques and applications
Machine learning covers a large set of algorithms that can be trained to identify patterns in data. Thanks to the increase in the amount of data and computing power available, it has become pervasive across scientific disciplines. We first highlight why machine learning is needed in marine ecology. Then we provide a quick primer on machine learning techniques and vocabulary. We built a database of ∼1000 publications that implement such techniques to analyse marine ecology data. For various data types (images, optical spectra, acoustics, omics, geolocations, biogeochemical profiles, and satellite imagery), we present a historical perspective on applications that proved influential, can serve as templates for new work, or represent the diversity of approaches. Then, we illustrate how machine learning can be used to better understand ecological systems, by combining various sources of marine data. Through this coverage of the literature, we demonstrate an increase in the proportion of marine ecology studies that use machine learning, the pervasiveness of images as a data source, the dominance of machine learning for classification-type problems, and a shift towards deep learning for all data types. This overview is meant to guide researchers who wish to apply machine learning methods to their marine datasets.Machine learning in marine ecology: an overview of techniques and applicationspublishedVersio
A Location-Aware Middleware Framework for Collaborative Visual Information Discovery and Retrieval
This work addresses the problem of scalable location-aware distributed indexing to enable the leveraging of collaborative effort for the construction and maintenance of world-scale visual maps and models which could support numerous activities including navigation, visual localization, persistent surveillance, structure from motion, and hazard or disaster detection. Current distributed approaches to mapping and modeling fail to incorporate global geospatial addressing and are limited in their functionality to customize search. Our solution is a peer-to-peer middleware framework based on XOR distance routing which employs a Hilbert Space curve addressing scheme in a novel distributed geographic index. This allows for a universal addressing scheme supporting publish and search in dynamic environments while ensuring global availability of the model and scalability with respect to geographic size and number of users. The framework is evaluated using large-scale network simulations and a search application that supports visual navigation in real-world experiments
Identificação de Fatores Determinantes
A pirataria marítima é atualmente um fenómeno com forte impacto na atividade
económica mundial. Atenta a sua natureza adaptativa e criminosa, tende a evoluir, quer
seja no espaço e nas formas de ataque em função das medidas de segurança e proteção
que são tomadas por parte dos estados costeiros e das potências marítimas que tomam a
iniciativa de prevenir esses mesmos ataques. Regra geral, é possível afirmar que este
fenómeno é mais comum em áreas que cruzam as rotas de comércio marítimo e onde se
verifica pouco controlo dos estados costeiros. O presente estudo, efetuado com os dados
disponibilizados pela InternationalMaritimeOrganization e pelo Centro de Gestão e
Análise de Dados Operacionais da Marinha Portuguesa, relativos aos últimos doze anos,
tem como objetivo apresentar uma análise exploratória dos dados e verificar se existem
padrões nos ataques de pirataria que permitam induzir conhecimento sobre as
caraterísticas do fenómeno, na perspectiva espacial e temporal. Para o efeito, foram
utilizadas abordagens estatísticas descritivas, recurso a sistemas de informação
geográfica e ao uso de Self-OrganizingMaps, definidos com uma, duas e três dimensões
no espaço de output com vista à identificação de eventuais padrões existentes nos
dados. Da análise efetuada foi possível relacionar os ataques de pirataria entre as áreas
afetadas bem como as semelhanças existentes entre eles. Da análise temporal efetuada
foi ainda possível analisar a evolução do fenómeno ao longo dos últimos anos.Maritime piracy is currently a phenomenon with a strong impact on global
economic activity. Aware of its adaptive and criminal nature, it tends to evolve, whether
in space and in the forms of attack depending on the security and protection measures
that are taken by coastal states and maritime powers that take the initiative to prevent
these same attacks. As a general rule, it can be said that this phenomenon is more
common in areas that cross maritime trade routes and where there is little control of
coastal states. This study, carried out with the data provided by the
InternationalMaritimeOrganization and the Center for Operational Data Management
and Analysis of the Portuguese Navy, for the last twelve years, aims to present an
exploratory analysis of the data and verify if there are patterns in piracy attacks that
allow to induce knowledge about the characteristics of the phenomenon, from a spatial
and temporal perspective. For this purpose, were used descriptive statistical approaches,
geographic information systems and Self-Organizing Maps, defined with one, two and
three dimensions in the output space in order to identify possible patterns in the data.
From the analysis performed it was possible to relate the piracy attacks between the
affected areas as well as the similarities between them. From the temporal analysis
carried out it was also possible to analyze the evolution of the phenomenon over the last
few years
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