Anastasia Moumtzidou

Building an Environmental Information System for Personalized Content Delivery

Citizens are increasingly aware of the influence of environmental and meteorological conditions on the quality of their life. This results in an increasing demand for personalized environmental information, i.e., information that is tailored to citizens’ specific context and background. In this work we describe the development of an environmental information system that addresses this demand in its full complexity. Specifically, we aim at developing a system that supports submission of user generated queries related to environmental conditions. From the technical point of view, the system is tuned to discover reliable data in the web and to process these data in order to convert them into knowledge, which is stored in a dedicated repository. At run time, this information is transferred into an ontology-structured knowledge base, from which then information relevant to the specific user is deduced and communicated in the language of their preference.

Discovery of environmental nodes in the web

Analysis and processing of environmental information is considered of utmost importance for humanity. This article addresses the problem of discovery of web resources that provide environmental measurements. Towards the solution of this domain-specific search problem, we combine state-of-the-art search techniques together with advanced textual processing and supervised machine learning. Specifically, we generate domain-specific queries using empirical information and machine learning driven query expansion in order to enhance the initial queries with domain-specific terms. Multiple variations of these queries are submitted to a general-purpose web search engine in order to achieve a high recall performance and we employ a post processing module based on supervised machine learning to improve the precision of the final results. In this work, we focus on the discovery of weather forecast websites and we evaluate our technique by discovering weather nodes for south Finland.

News Articles Classification Using Random Forests and Weighted Multimodal Features

This research investigates the problem of news articles classification. The classification is performed using N-gram textual features extracted from text and visual features generated from one representative image. The application domain is news articles written in English that belong to four categories: Business-Finance, Lifestyle-Leisure, Science-Technology and Sports downloaded from three well-known news web-sites (BBC, Reuters, and TheGuardian). Various classification experiments have been performed with the Random Forests machine learning method using N-gram textual features and visual features from a representative image. Using the N-gram textual features alone led to much better accuracy results (84.4%) than using the visual features alone (53%). However, the use of both N-gram textual features and visual features led to slightly better accuracy results (86.2%). The main contribution of this work is the introduction of a news article classification framework based on Random Forests and multimodal features (textual and visual), as well as the late fusion strategy that makes use of Random Forests operational capabilities.

Environmental data extraction from multimedia resources

Extraction and analysis of environmental information is very important, since it strongly affects everyday life. Nowadays there are already many free services providing environmental information in several formats including multimedia (e.g. map images). Although such presentation formats might be very informative for humans, they complicate the automatic extraction and processing of the underlying data. A characteristic example is the air quality and pollen forecasts, which are usually encoded in image maps, while the initial (numerical) pollutant concentrations remain unavailable. This work proposes a framework for the semi-automatic extraction of such information based on a template configuration tool, on Optical Character Recognition (OCR) techniques and on methodologies for data reconstruction from images. The system is tested with a different air quality and pollen forecast heatmaps demonstrating promising results.

VERGE: A video interactive retrieval engine

This paper presents the video retrieval engine VERGE, which combines indexing, analysis and retrieval techniques in various modalities (i.e. textual, visual and concept search). The functionalities of the search engine are demonstrated through the supported user interaction modes.

Personalized Environmental Service Orchestration for Quality of Life Improvement

Environmental and meteorological conditions are of utmost importance for the population, as they are strongly related to the quality of life. Citizens are increasingly aware of this importance. This awareness results in an increasing demand for environmental information tailored to their specific needs and background. We present an environmental information platform that supports submission of user queries related to environmental conditions and orchestrates results from complementary services to generate personalized suggestions. From the technical viewpoint, the system discovers and processes reliable data in the web in order to convert them into knowledge. At run time, this information is transferred into an ontology-structured knowledge base, from which then information relevant to the specific user is deduced and communicated in the language of their preference. The platform is demonstrated with real world use cases in the south area of Finland showing the impact it can have on the quality of everyday life.

A hybrid graph-based and non-linear late fusion approach for multimedia retrieval

Nowadays, multimedia retrieval has become a task of high importance, due to the need for efficient and fast access to very large and heterogeneous multimedia collections. An interesting challenge within the aforementioned task is the efficient combination of different modalities in a multimedia object and especially the fusion between textual and visual information. The fusion of multiple modalities for retrieval in an unsupervised way has been mostly based on early, weighted linear, graph-based and diffusion-based techniques. In contrast, we present a strategy for fusing textual and visual modalities, through the combination of a non-linear fusion model and a graph-based late fusion approach. The fusion strategy is based on the construction of a uniform multimodal contextual similarity matrix and the non-linear combination of relevance scores from query-based similarity vectors. The proposed late fusion approach is evaluated in the multimedia retrieval task, by applying it to two multimedia collections, namely the WIKI11 and IAPR-TC12. The experimental results indicate its superiority over the baseline method in terms of Mean Average Precision for both considered datasets.

A Unified Model for Socially Interconnected Multimedia-Enriched Objects

Enabling effective multimedia information processing, analysis, and access applications in online social multimedia settings requires data representation models that capture a broad range of the characteristics of such environments and ensure interoperability. We propose a flexible model for describing Socially Interconnected MultiMedia-enriched Objects (SIMMO) that integrates in a unified manner the representation of multimedia and social features in online environments. Its specification is based on a set of identified requirements and its expressive power is illustrated using several diverse examples. Finally, a comparison of SIMMO with existing approaches demonstrates its unique features.

VERGE: An Interactive Search Engine for Browsing Video Collections

This paper presents VERGE interactive video retrieval engine, which is capable of searching and browsing video content. The system integrates several content-based analysis and retrieval modules such as video shot segmentation and scene detection, concept detection, clustering and visual similarity search into a user friendly interface that supports the user in browsing through the collection, in order to retrieve the desired clip.

Discovery of environmental resources based on heatmap recognition

Environmental data are considered of utmost importance for human life, since weather conditions, air quality and pollen are strongly related to health issues and affect everyday activities. This paper addresses the problem of discovery of air quality and pollen forecast Web resources, which are usually presented in the form of heatmaps (i.e. graphical representation of matrix data with colors). Towards the solution of this problem, we propose a discovery methodology, which builds upon a general purpose search engine and a novel post processing heatmap recognition layer. The first step involves generation of domain-specific queries, which are submitted to the search engine, while the second involves an image classification step based on visual low level features to identify Web sites including heatmaps. Experimental results comparing various visual features combinations show that relevant environmental sites can be efficiently recognized and retrieved.