Stasinos Konstantopoulos

National Center for Scientific Research Demokritos | ncsr · Insititute of Informatics and Telecommunications

In this paper we explore the correlation between the sound of words and their meaning, by testing if the polarity ("good guy" or "bad guy") of a character's role in a work of fiction can be predicted by the name of the character in the absence of any other context. Our approach is based on phonological and other features proposed in prior theoretic...

Processing SPARQL queries involves the construction of an efficient query plan to guide query execution. Alternative plans can vary in the resources and the amount of time that they need by orders of magnitude, making planning crucial for efficiency. On the other hand, the construction of optimal plans can become computationally intensive and it al...

Query processing systems typically rely on histograms, data structures that approximate data distribution, in order to optimize query execution. Histograms can be constructed by scanning the database tables and aggregating the values of the attributes in the table, or, more efficiently, progressively refined by analysing query results. Most of the...

In this paper we present a novel method for detecting humans from laser range scans, where the core idea is to treat neither individual frames, which hold so little information that the task is impossible, nor motion patterns, as is the case with tracking methods. Rather, we map short time series of planar scans to 3D objects with time as the depth...

This paper presents work in progress towards developing a new benchmark for federated query processing systems. Unlike other popular benchmarks, our queryset is not driven by technical evaluation, but is derived from workflows established by the pharmacology community. The value of this queryset is that it is realistic but at the same time it compr...

Background: Geospatial linked data brings into the scope of the Semantic Web and its technologies, a wealth of datasets that combine semantically-rich descriptions of resources with their geo-location. There are, however, various Semantic Web technologies where technical work is needed in order to achieve the full integration of geospatial data, an...

Background : Geospatial linked data brings into the scope of the Semantic Web and its technologies, a wealth of datasets that combine semantically-rich descriptions of resources with their geo-location. There are, however, various Semantic Web technologies where technical work is needed in order to achieve the full integration of geospatial data, a...

The European fusion research activities have over the last decades generated a vast and varied set of data. The volume and diversity of the data that need to be catalogued and annotated make the task of organising and making the data available within a broader environment very challenging. Nevertheless, there are strong scientific drivers as well a...

Background: In geospatial query processing, spatial containment and intersection queries can be efficiently answered from the index. There is, however, a class of queries (such as within-distance ) with a semantics that implies that every shape in the database is a potential match and should, in principle, be compared with the threshold. Naturally,...

Background : Geospatial linked data brings into the scope of the Semantic Web and its technologies, a wealth of datasets that combine semantically-rich descriptions of resources with their geo-location. There are, however, various Semantic Web technologies where technical work is needed in order to achieve the full integration of geospatial data, a...

Training on simulation data has proven invaluable in applying machine learning in robotics. However, when looking at robot vision in particular, simulated images cannot be directly used no matter how realistic the image rendering is, as many physical parameters (temperature, humidity, wear-and-tear in time) vary and affect texture and lighting in w...

Traversability illustrates the difficulty of driving through a specific region and encompasses the suitability of the terrain for traverse based on its physical properties, such as slope and roughness, surface condition, etc. In this survey we highlight the merits and limitations of all the major steps in the evolution of traversability estimation...

Bringing together a number of cutting-edge technologies that range from storing extremely large volumesof data all the way to developing scalable machine learning and deep learning algorithms in a distributed manner, and having them operate over the same infrastructure poses unprecedentedchallenges. One of these challenges is the integration of Eur...

In the SPARQL query processing community, as well as in the wider databases community, benchmark reproducibility is based on releasing datasets and query workloads. However, this paradigm breaks down for federated query processors, as these systems do not manage the data they serve to their clients but provide a data-integration abstraction over th...

ExtremeEarth is a three-year H2020 ICT research and innovation project. Its main objective is to develop Artificial Intelligence and big data technologies that scale to the large volumes of big Copernicus data, information and knowledge, and apply these technologies in two of the European Space Agency (ESA) Thematic Exploitation Platforms (TEP): Fo...

Low-cost and widely available Next-Generation Sequencing (NGS) is revolutionizing clinical practice, paving the way for the realization of precision medicine. Applying NGS to clinical practice requires establishing a complex loop involving sample collection and sequencing, computational processing of the NGS outputs to identify variants, and the in...

Health care platforms rapidly shift toward the ICT-based solutions. In this context, a wide range of consumer electronics technologies come into play ranging from robotics, embedded systems, sensors, and communication infrastructures. Driven by such observations, the H2020 RADIO project set forward a service-oriented, easily expandable design parad...

This White Paper aims to set out the National AI Strategic Vision for Greece and to provide an initial plan of action on how to achieve this vision. It aims to accelerate the adoption and development of AI in both the private and public sectors in Greece and increase the relevant skills and the research and development (R&D) base through the provis...

The ability to have unmanned ground vehicles navigate unmapped off-road terrain has high impact potential in application areas ranging from supply and logistics, to search and rescue, to planetary exploration. To achieve this, robots must be able to estimate the traversability of the terrain they are facing, in order to be able to plan a safe path...

Demographic and epidemiologic transitions have brought a new health care paradigm with the presence of both growing elderly population and chronic diseases. Life expectancy is increasing as well as the need for long-term care. Institutional care for the aged population faces economical struggles with low staffing ratios and consequent quality probl...

Robotic, smart home and other related technologies that are integrated in AAL environments should be combined and presented to their users in an unobtrusive way. Obtrusiveness is a subjective, multidimensional, environment-dependent and multi-target concept that is used to describe how various technologies can negatively impact the daily lives of t...

As smart interconnected sensing devices are becoming increasingly ubiquitous, more applications are becoming possible by re-arranging and re-connecting sensing and sensor signal analysis in different pipelines. Naturally, this is best facilitated by extremely thin services that expose minimal functionality and are extremely flexible regarding the w...

Multiple RADIO home deployments, healthcare services providers, and medical researchers make up an ecosystem where different actors have different access rights to the data collected by RADIO monitoring. This chapter presents the two different access modes and technologies that support them: access controls to individual users’ data for the purpose...

Copernicus is the European programme for monitoring the Earth. It consists of a set of systems that collect data from satellites and in-situ sensors, process this data and provide users with reliable and up-to-date information on a range of environmental and security issues. The data and information processed and disseminated puts Copernicus at the...

The purpose of the RADIO system is to supprt independent ageing by providing assistance to its primary users. At the same time, it monitors severa] Activities of Daily Living ( ADLs) and collects clinically rclatcd information so that the clinical staff and/or informal caregivers (secondary users) can assess the level of indepen­dency of the elderl...

This paper presents work on detecting and tracking human movement in planar range data. Our method stacks multiple planar scans into a 3D frame where time serves as the third dimension. This representation simultaneously informs about the size and shape of the objects in the scene and about their movement, so that no explicit motion models are nece...

Demographic and epidemiologic transitions have brought a new health care paradigm where life expectancy is increasing as well as the need for long-term care. To meet the resulting challenge, healthcare systems need to take full advantage of new opportunities offered by technical advancements in ICT. The RADIO project explores a novel approach to us...

In this paper we present SPREFQL, an extension of the SPARQL language that allows appending a PREFER clause that expresses "soft" preferences over the query results obtained by the main body of the query. The extension does not add expressivity and any SPREFQL query can be transformed to an equivalent standard SPARQL query. However, clearly separat...

Emergencies that involve the release of hazardous substances into the atmosphere affects life and nature for several years. The timely and reliable estimation of the expected consequences on people and the environment facilitates informed decision making and timely response. Here, we demonstrate a tool that leverages Big Data and Semantic Web techn...

Dataset description vocabularies focus on provenance, ver-sioning, licensing, and similar metadata. VoID is a notable exception, providing some expressivity for describing subsets and their contents and can, to some extent, be used for discovering relevant resources and for optimizing querying. In this paper we describe the Sevod vocabulary, an ext...

A framework that utilizes audio information for recognition of activities of daily living (ADLs) in the context of a health monitoring environment is presented in this chapter. We propose integrating a Raspberry PI single-board PC that is used both as an audio acquisition and analysis unit. So Raspberry PI captures audio samples from the attached m...

The management and analysis of large-scale datasets – described with the term Big Data – involves the three classic dimensions volume, velocity and variety. While the former two are well supported by a plethora of software components, the variety dimension is still rather neglected. We present the BDE platform – an easy-to-deploy, easy-to-use and a...

This paper presents a method for recognizing activities taking place in a home environment. Audio is recorded and analysed realtime, with all computation taking place on a low-cost Raspberry PI. In this way, data acquisition, low-level signal feature calculation, and low-level event extraction is performed without transferring any raw data out of t...

As robot capabilities increase, the complexity of controlling and manipulating them becomes complex and cumbersome making intuitive Human-Robot Interaction all the more necessary for seamless human-robot collaboration. In this paper, we look into the ability of collaborators to understand each other's intentions and act accordingly in order to prom...

This article discusses the concept that proper names are not semantically empty denotations, but characterize in many, often subliminal, ways their denotee. The discussion is driven by computational experiments on using just a name to guess the linguistic and cultural background of a person and the positive or negative polarity of a fictional chara...

A brief overview of the crowd-sourcing tools developed within the analytical platform of the PREPARE project is presented. Crowd sourcing relates to methods that: offer a Web Content Discovery Service that automatically acquires and analyses content from social networks and the Web to extract information during nuclear or radiological (NR) events a...

As smart interconnected sensing devices are becoming increasingly ubiquitous, more applications are becoming possible by re-arranging and re-connecting sensing and sensor signal analysis in different pipelines. Naturally, this is best facilitated by extremely thin services that expose minimal functionality and are extremely flexible regarding the w...

The insights gained by the large-scale analysis of health-related data can have an enormous impact in public health and medical research, but access to such personal and sensitive data poses serious privacy implications for the data provider and a heavy data security and administrative burden on the data consumer. In this paper we present an archit...

This paper introduces a framework that allows humans to give highly abstract navigation instructions to mobile robots. It uses simultaneous localisation and mapping (SLAM) to navigate a mobile robot through an unknown environment and combines it with a structured, pseudo-human language for describing the navigation instructions. This combination al...

In this paper, we present an architecture for recognizing events related to activities of daily living in the context of a health monitoring environment. The proposed approach explores the integration of a Raspberry PI singleboard PC both as an audio acquisition and analysis unit. A set of real-time feature extraction and classification procedures...

Demographic and epidemiologic transitions have brought forward a new health care paradigm with the presence of both growing elderly population and chronic diseases. Recent technological advances can support elderly people in their domestic environment assuming that several ethical and clinical requirements can be met. This paper presents an archite...

In this paper we propose a method for detecting metaphorical usage of content terms based on the hypothesis that metaphors can be detected by being characteristic of a different domain than the one they appear in. We formulate the problem as one of extracting knowledge from text classification models, where the latter have been created using standa...

In this paper we extend STHoles, a very successful algorithm that uses query results to build and maintain multi-dimensional histograms of numerical data. Our contribution is the formal definition of extensions of all relevant concepts; such that they are independent of the domain of the data, but subsume STHoles concepts as their numerical special...

The social media revolution is having a dramatic effect on the world of scientific publication. Scientists now publish their research interests, theories and outcomes across numerous channels, including personal blogs and other thematic web spaces where ideas, activities and partial results are discussed. Accordingly, information systems that facil...

Using robotic home assistants as a platform for remote health monitoring offers several advantages, but also presents considerable challenges related to both the technical immaturity of home robotics and to user acceptance issues. In this paper we explore tablets and similar mobile devices as the medium of communication between robots and their use...

Demographic and epidemiologic transitions in Europe have brought a new health care paradigm where life expectancy is increasing as well as the need for long-term care. To meet the resulting challenge, European healthcare systems need to take full advantage of new opportunities offered by technical advancements in ICT. The RADIO project explores a n...

Dataset description vocabularies focus on provenance, versioning, licensing, and similar metadata. VoID is a notable exception, providing some expressivity for describing subsets and their contents and can, to some extent, be used for discovering relevant resources and for optimizing querying. In this poster we describe an extension of VoID that pr...

The purpose of the research described in this paper is to examine the existence of correlation between low level audio, visual and textual features and movie content similarity. In order to focus on a well defined and controlled case, we have built a small dataset of movie scenes from three sequel movies. In addition, manual annotations have led to...

A novel implementation is presented for NREO, a subject-specific ontology of the Nuclear or Radiological Emergency domain. The ontology design is driven by the requirements of ontology-based, multi-lingual language processing and retrieval use cases, but care is taken to architect the foundations in a way that can be extended to support other use c...

Using robotic home assistants as a platform for remote health monitoring offers several advantages, but also presents considerable challenges related to both the technical immaturity of home robotics and to user acceptance issues. In this paper we explore tablets and similar mobile devices as the medium of communication between robots and their use...

In logic programming, a thread of input/output variables is often used to carry state information through the body literals of the clauses that make up a logic program. When using inductive logic programming (ILP) to synthesise logic programs, the standard refinement operators that define the search space cannot enforce this pattern and non-conform...

In recent years, innovative applications exploiting Linked Open Data (LOD) and the Semantic Web have opened up, combined and cross referenced high volumes of high-quality data and created tremendous new opportunities for data users as well as data providers. However, in order to serve the broadest community of users, technologies need to be develop...

In this paper we motivate and present our embodied visual programming research plan, aiming at allowing end-users without any technical expertise to define complex robot behaviours. The core idea is to combine visual programming with the sensing and actuation capabilities of robots and with teleoperated demonstrations of what needs to be achieved.

In this paper, we present RoboMAE, a multi-modal sensor data annotation environment that allows humans to concentrate on high-level decisions producing full frame-by-frame annotations. Multi-modal annotation tools focus on interpreting a scene by annotating data on separate modalities. In this work, we focus on the cross-linking of the same object'...

Traditional Artificial Cognitive Systems (for example, intelligent robots) share a number of limitations. First, they are usually made up only of machine components; humans are only playing the role of user or supervisor. And yet, there are tasks in which the current state of the art of AI has much worse performance or is more expensive than humans...

The POWDER protocol is a Semantic Web technology --and W3C Recommendation- that takes advantage of natural groupings of URIs, as identifiers as well as navigational paths, to annotate all the resources in a regular expression-delineated sub-space of the URI space. POWDER was designed as a mechanism for accreditation, trustmarking and resource disco...

In this paper we describe an application of language technology to policy formulation, where it can support policy makers assess the acceptance of a yet-unpublished policy before the policy enters public consultation. One of the key concepts is that instead of relying on thematic similarity, we extract arguments expressed in support or opposition o...

Dataset used for Florou et al., "Argument extraction for supporting public policy formulation", LaTeCH 2013, Sofia, August 2013.

We present a novel approach to recognizing patterns in laser range data that per-forms on a par with the state of the art while at the same time requiring minimal param-eters and supervision. Most importantly, supervision is only needed at the level of real-world objects that a robot can interact with (humans, in our experiments). This is an import...

It has been demonstrated that human users attribute a personality to the computer interfaces they use, regardless of whether one has been explicitly encoded in the system's design or not. In this paper, we explore a method for having explicit control over the personality that a spoken human-robot interface is perceived to exhibit by its users. Our...

The POWDER protocol is a Semantic Web technology that takes advantage of natural groupings of URIs to annotate all the resources in a regular expression-delineated sub-space of the URI space. POWDER is a mechanism for accreditation, trustmarking and resource discovery, emphasising the publishing of attributed metadata by third parties and trusted a...

Adaptive content selection is recognized as a challenging research is-sue in adaptive educational hypermedia systems (AEHS). Several efforts have been reported in literature aiming to support the Adaptation Model (AM) design by providing AEHS designers with either guidance for the direct definition of adaptation rules, or semi-automated mechanisms...

Current approaches to the interoperability of heterogeneous re-sources typically maintain coordinated clones over which querying infra-structure operates. In the case of large-scale repositories, and especially when no single schema is clearly established so that the problem can be reduced to transforming legacy data, a more dynamic approach would...

In this paper we present and discuss the implementation and deployment of the Protocol for Web Description Resources (POWDER) W3C Recommendation for a large RDF repository containing millions of triples. POWDER enables taking advantage of natural groupings of URIs and their reflection on the denoted things' properties; our application implements a...

Analysing Nordic persons' names with respect to language identification is a very hard task, as the chosen group of languages is closely related, but provides interesting insights into the structure of names; it is also a task that has many applications in information extraction, speech synthesis, and automatic transliteration. In this paper we pre...

We present the ELEON/NATURALOWL system, an application of Semantic Web and Natural Language Generation technologies that combines a conceptual representation of cultural heritage objects with linguistic and adaptation resources. This combined model is used to automatically generate multi-lingual and personalized textual descriptions of cultural her...

We describe an Inductive Logic Programming (ILP) approach to learning descriptions in Description Logics (DL) under uncertainty. The approach is based on implementing many-valued DL proofs as propositionalizations of the elementary DL constructs and then providing this implementation as background predicates for ILP. The proposed methodology is tes...

An enduring challenge in human-computer interaction (HCI) research is the creation of natural and intuitive interfaces. Besides the obvious requirement that such interfaces communicate over modalities such as natural language (especially spo-ken) and gesturing that are more natural for humans, exhibiting affect and adaptiv-ity have also been identi...

This demonstration aims to show specific technological advancements that enable cognitive based robots to perceive and understand natural human behavior as well as to act in ways that are familiar to humans. The demonstration is built around a museum guide use-case, where a simulated robotic guide is operating in a virtual environment. During the d...