showing 23 related works from this author
An enhanced random walk algorithm for delineation of head and neck cancers in PET studies
2017
An algorithm for delineating complex head and neck cancers in positron emission tomography (PET) images is presented in this article. An enhanced random walk (RW) algorithm with automatic seed detection is proposed and used to make the segmentation process feasible in the event of inhomogeneous lesions with bifurcations. In addition, an adaptive probability threshold and a k-means based clustering technique have been integrated in the proposed enhanced RW algorithm. The new threshold is capable of following the intensity changes between adjacent slices along the whole cancer volume, leading to an operator-independent algorithm. Validation experiments were first conducted on phantom studies:…
Description of Dynamic Structured Scenes by a SOM/ARSOM Hierarchy
2001
A neural architecture is presented, aimed to describe the dynamic evolution of complex structures inside a video sequence. The proposed system is arranged as a tree of self-organizing maps. Leaf nodes are implemented by ARSOM networks as a way to code dynamic inputs, while classical SOM's are used to implement the upper levels of the hierarchy. Depending on the application domain, inputs are made by suitable low level features extracted frame by frame of the sequence. Theoretical foundations of the architecture are reported along with a detailed outline of its structure, and encouraging experimental results.
Optic disc positioning and blood vessels extraction on eye fundus
2009
This paper presents two methods aimed to the optic disc positioning on the retinal images. The first is based on a template of the entire image, while the second is based on the retinal vascularisation. For this second task, also a vessel extraction method is provided. Both the algorithm have been tested on test images of the Drive Database.
A framework to induce self-regulation through a metacognitive tutor
2010
A new architectural framework for a metacognitive tutoring system is presented that is aimed to stimulate self regulatory behavior in the learner. The new framework extends the cognitive architecture of TutorJ that has been already proposed by some of the authors. TutorJ relies mainly on dialogic interaction with the user, and makes use of a statistical dialogue planner implemented through a Partially Observable Markov Decision Process (POMDP). A suitable two-level structure has been designed for the statistical reasoner to cope with measuring and stimulating metacognitive skills in the user. Suitable actions have been designed to this purpose starting from the analysis of the main question…
Fostering Teacher-Student Interaction and Learner Autonomy by the I-TUTOR Maps
2014
The paper analyses the use of an automatically generated map as a mediator; that map visually represents the study domain of a university course and fosters the co-activity between teachers and stu- dents. In our approach the role of the teacher is meant as a media- tor between the student and knowledge. The mediation (and not the transmission) highlights a process in which theres no deterministic rela- tion between teaching and learning. Learning is affected by the students previous experiences, their own modalities of acquisition and by the in- puts coming from the environment. The learning path develops when the teachers and the students visions approach and, partly, overlap. In this cas…
An automatic method for metabolic evaluation of gamma knife treatments
2015
Lesion volume delineation of Positron Emission Tomography images is challenging because of the low spatial resolution and high noise level. Aim of this work is the development of an operator independent segmentation method of metabolic images. For this purpose, an algorithm for the biological tumor volume delineation based on random walks on graphs has been used. Twenty-four cerebral tumors are segmented to evaluate the functional follow-up after Gamma Knife radiotherapy treatment. Experimental results show that the segmentation algorithm is accurate and has real-time performance. In addition, it can reflect metabolic changes useful to evaluate radiotherapy response in treated patients.
Awareness Mechanisms for an Intelligent Tutoring System
2008
In this work an Intelligent Tutoring System (ITS) is presented that is able to enrich its knowledge base, merging both partially structured and unstructured information in a unique internal representation framework. The system gathers new information about the domain in response to both a curiosity mechanism and sensory stimuli coming from the interaction with the user. The architecture is an evolution of TutorJ, an actual ITS already presented by some of the authors. The cognitive framework is a very promising one to overcome the limitations of classical ITSs, and to achieve the stated goal. The use of cognitive architectures is intended for a double result: a lower effort for a knowledge-…
Automatic aesthetic photo composition
2013
A proper aesthetic composition of photographic content does result in an actual emotional response from the watcher. In this work we propose a fully automatic computational approach to photo composi- tion. This method takes into account well-known and widely adopted aesthetic guidelines relative to picture content as a mean for guiding an optimization framework. The resulting composition is produced as the optimal combination of cropping and retargeting. The effectiveness of the results achieved by the method are tested and evaluated with several of experiments.
Retargeting Framework Based on Monte-carlo Sampling
2015
Advance in image technology and proliferation of acquisition devices like smartphones, digital cameras, etc., made the display of digital images ubiquitous. Many displays exist in the market, spanning within a large variety of resolutions and shapes. Thus, displaying content optimizing the available number of pixels has become a very important issue in the multimedia community, and the image retargeting problem is being widely faced. In this work, we propose an image retargeting framework based on monte-carlo sampling. We operate the non-homogeneous resizing as the composition of several simple atomic resizing functions. The shape of such atomic operator can be chosen within a set of tested…
Towards Mkda: A Data Mining Semantic Web Service
2008
Nowadays a huge amount of raw medical data is generated. These data, analyzed with data mining techniques, could be used to produce new knowledge. Unluckily such tasks need skilled data analysts, and not so many researchers in medical field are also data mining experts. In this paper we present a web based system for knowledge discovery assistance in Medicine able to advice a medical researcher in this kind of tasks. The experiment specifications are expressed in a formal language we have defined. The system GUI helps the user in the their composition. The system plans a Knowledge Discovery Process (KDP). The KDP is designed on the basis of rules in a knowledge base. Finally the system exec…
Information Organization and Visualization for the ALS Project
2010
This work presents the adopted methodology and the realized tools for data visualization in the Linguistic Atlas Of Sicily (ALS) Project. The ALS Project has the purpose to discovery new trends and variables to track the linguistic evolution over time and space in Sicily. The project is focused on how linguistic variables are related to social and economic aspects of the evolution of population and vice-versa. The visualization tools are a relevant aspect of the project to support decisions and disseminate results. One of the major factors is the geographic dependence of data evolution. To this aim complex set of tools has been developed: some tools are stand-alone while others are collabor…
XML-based Knowledge Discovery for Linguistic Atlas of Sicily (ALS) Project
2009
The identification of new useful patterns in data is a core process for intelligent systems. Information overflow is directly related to this problem. In this work we propose a knowledge discovery methodology to retrieve useful and novel information from raw data stored in a DBMS. We used ALSDB, a database that has been built suitably to access structured information obtained from the questionnaires produced in the Linguistic Atlas of Sicily (ALS) project. The ALS project is a decennal joint effort led by researchers at the Dipartimento di Scienze Filologiche e Linguistiche of the University of Palermo that has the purpose to track and study the geo-linguistic and lexicographic processes ab…
MultiSlice human organ extraction based on GVF
2008
Segmentation techniques based on active contours algorithm are widely used in medical imaging. Unfortunately, they require a lot of parameters to be used and this can rep- resent an issue for those physicians with not much informatics skills. This paper proposes a software tool which allows to segment multiple slice can differ organ extraction setting a small number of parameters. Moreover, the tool offers the functionality to perform a multiple segmentation the same time, so that an entire volume composed by hundreds slices can be segmented.
Automatic Volumetric Liver Segmentation Using Texture Based Region Growing
2010
In this paper an automatic texture based volumetric region growing method for liver segmentation is proposed. 3D seeded region growing is based on texture features with the automatic selection of the seed voxel inside the liver organ and the automatic threshold value computation for the region growing stop condition. Co-occurrence 3D texture features are extracted from CT abdominal volumes and the seeded region growing algorithm is based on statistics in the features space. Each CT volume is composed by 230 slices, having 512 x 512 pixels as spatial resolution, and 12-bit gray level resolution. In this initial feasible study, 5 healthy volunteer acquisitions has been used. Tests have been p…
Frequency Determined Homomorphic Unsharp Masking Algorithm on Knee MR Images
2005
A very important artifact corrupting Magnetic Resonance (MR) Images is the RF inhomogeneity, also called Bias artifact. The visual effect produced by this kind of artifact is an illumination variation which afflicts this kind of medical images. In literature a lot of works oriented to the suppression of this artifact can be found. The approaches based on homomorphic filtering offer an easy way to perform bias correction but none of them can automatically determine the cut-off frequency. In this work we present a measure based on information theory in order to find the frequency mentioned above and this technique is applied to MR images of the knee which are hardly bias corrupted.
Texture classification for content-based image retrieval
2002
An original approach to texture-based classification of regions, for image indexing and retrieval, is presented. The system addresses automatic macro-textured ROI detection, and classification: we focus our attention on those objects that can be characterized by a texture as a whole, like trees, flowers, walls, clouds, and so on. The proposed architecture is based on the computation of the /spl lambda/ vector from each selected region, and classification of this feature by means of a pool of suitably trained support vector machines (SVM). This approach is an extension of the one previously developed by some of the authors to classify image regions on the basis of the geometrical shape of th…
Automatic skull stripping in MRI based on morphological filters and fuzzy c-means segmentation
2012
In this paper a new automatic skull stripping method for T1-weighted MR image of human brain is presented. Skull stripping is a process that allows to separate the brain from the rest of tissues. The proposed method is based on a 2D brain extraction making use of fuzzy c-means segmentation and morphological operators applied on transversal slices. The approach is extended to the 3D case, taking into account the result obtained from the preceding slice to solve the organ splitting problem. The proposed approach is compared with BET (Brain Extraction Tool) implemented in MRIcro software.
Browser independent content based image resizing for liquid web layouts
2010
A typical problem for webdesigners is to realize pages that can be potentially accessed from a number of display devices with different screen sizes and resolutions. Liquid layouts can help for this purpose. However, they can not typically be applied to images, which need to be rescaled or deformed. In both cases usability could be deteriorated. Content-aware image resizing techniques can help for this goal by rescaling the images to the desired width while preserving important image structures. This paper presents a content-aware resizing technique which can be seamlessly integrated into web pages without any effort from the user. The results from the system application prove its effective…
A Cognitive Dialogue Manager for Education Purposes
2011
A conversational agent is a software system that is able to interact with users in a natural way, and often uses natural language capabilities. In this chapter, an evolution of a conversational agent is presented according to the definition of dialogue management techniques for the conversational agents. The presented conversational agent is intended to act as a part of an educational system. The chapter outlines the state-of-the-art systems and techniques for dialogue management in cognitive educational systems, and the underlying psychological and social aspects. We present our framework for a dialogue manager aimed to reduce the uncertainty in users’ sentences during the assessment of hi…
Head–Neck Cancer Delineation
2021
Head–Neck Cancer (HNC) has a relevant impact on the oncology patient population and for this reason, the present review is dedicated to this type of neoplastic disease. In particular, a collection of methods aimed at tumor delineation is presented, because this is a fundamental task to perform efficient radiotherapy. Such a segmentation task is often performed on uni-modal data (usually Positron Emission Tomography (PET)) even though multi-modal images are preferred (PET-Computerized Tomography (CT)/PET-Magnetic Resonance (MR)). Datasets can be private or freely provided by online repositories on the web. The adopted techniques can belong to the well-known image processing/computer-vision a…
WikiArt: An Ontology-Based Information Retrieval System for Arts
2009
The paper presents WikiArt, a new system integrating three distinct types of contents about the art: data, information, and knowledge, to generate automatically thematic paths to consult all its contents. WikiArt is a wiki, allowing to manage cooperatively documents about artists, artworks, artistic movements or techniques, and so on. It is also an expert system, provided with an ontology about arts, with which it is able to plan possible different ways of consulting and browsing its contents. This ability is made possible by a second part of the ontology of the system, describing a collection of criteria regarding how to plan thematic paths, and by a set of rules followed by the expert sys…
A Java 3D Talking Head for a Chatbot
2008
Facial animation is referred to all those systems per- forming the speech synchronization with an animated face model. This kind of systems are called ”Talking Head” or ”Talking Face”. In this paper a Talking Head oriented to the creation of a Chatbot is presented. It requires an in- put query and an answer is generated in form of text. The answer is transduced into a facial animation using a 3D face model whose lips movements are synchronized with the sound produced by a speech synthesis module. Our ”Talk- ing Head” explores the naturalness of the facial animation and provides a real-time interactive interface to the user. The WEB infrastructure has been realized using the Client- Server m…
Automatic concept maps generation in support of educational processes
2014
A VLE is a system where three main actors can be devised: the teacher in the role of instructional designer, the tutor, and the stu- dent. Instructional designers need easy interaction for specifying the course domain structure to the system, and for controlling how well the learning materials agree to such a structure. Tutors need tools for having a holistic perception of the evolution of single students and/or groups in the VLE during the learning process. Finally, students need self regulation in terms of controlling their learning rate, reflect on their learning strategies, and comparing with other people in the class. In this work we claim that sharing an implicit representation of the…