1,721,147 research outputs found
"Interaction Analysis with A Bayesian Trajectory Model"
No full textHuman behavior recognition is one of the most important and challenging objectives performed by intelligent vision systems. Several issues must be faced in this domain ranging from the extraction of reliable and meaningful features from video streams, to the accurate definition of models able to characterize in a discriminative but, at the same time, general enough way people actions. In this work to cope with these problems a Dynamic Bayesian Network (DBN) model is proposed to recognize people interactions using their patterns of movement. Couples of observed interacting trajectories are processed by the Instantaneous Topological Map (ITM) algorithm to automatically create a topological map used to define the states of the DBN. The trajectories are encoded into the model where conditional probability densities are learned in order to statistically describe interactions. Finally, an online cumulative measure is defined to recognize interactions both in simulated and real-world environments.
In this work instead of considering the trajectories independently one from another, we focus on the analysis of motion dependencies between couple of persons to recognize interactions. This choice is motivated by the fact that often human actions are interpretable only if the context is also taken into consideration. For example, a meeting situation can be detected only by identifying that a person is still because he is talking with someone in front of him/her. A statistical representation of interactions based on Dynamic Bayesian Networks (DBNs) is proposed to encode causal relationship in a probabilistic framework and classify unknown couples of trajectories. The Instantaneous Topological Map (ITM) algorithm is used to define the state of the DBN in an online way by creating a topological map based on trajectory observations. The states of the DBN are motion events defined in the map that are used to represent interactions in terms of cause/effect relationships. The proposed model presents the following properties: 1) the trajectory representation is not dependent to the starting point; 2) it is able to represent trajectories sampled with different number of points; 3) it is robust to tracking error and local track loss; 4) it makes possible to classify interactions in an online way; 5) it is easily adaptable to a new scenario. The paper is organized as follows: in Section II an overview of previous works on trajectory modeling and
interaction recognition is provided. In Section III the bio-inspired model of interaction and its representation into a Dynamic Bayesian Networks framework are proposed with the aim to model and classify interactive trajectories. In Section IV the discrimination capabilities of the proposed representation for different types of interactive trajectories are shown and finally, in Section V conclusions are drawn
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Multitarget Tracking with a Corner-based Particle Filter
No full textThis paper presents a multitarget tracking algorithm based on a particle filter framework that exploits a sparse distributed shape model to handle partial occlusions. The state vector is composed by a set of points of interest (i.e. corners) and it enables to jointly describe position and shape of the target. An efficient importance sampling strategy is developed to limit the number of used particles and it is based on multiple Kanade-Lucas-Tomasi (KLT) feature trackers used to estimate local motion. The importance sampling strategy adaptively handles KLT failures and partial occlusions. Particles weights are computed exploiting a shape matching technique combined with object local appearance encoded in color histograms of patches centered on the points of interest constituting the state. The proposed approach does not require background subtraction techniques and overcomes several common difficulties in the tracking domain as partial occlusions, object deformations, scale changes, abrupt motion and non-static background. Extensive experimental results are provided on challenging sequences to demonstrate the robustness of the algorithm
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
COMPARATIVE STUDY ON THE USE OF A NON-DESTRUCTIVE OPTICAL SENSOR (MULTIPLEX3®) FOR THE MONITORING OF THE ANTHOCYANINS CONTENT IN RED BERRY FRUITS
No full textThe preliminary results of a comparative study on the determination
of the anthocyanins content in red berry fruits by a portable fluorescence-
based optical sensor (Multiplex 3®) are reported. Commercially
available Multiplex 3® was used to measure the “Fluorescence
Excitation Ratio Anthocyanin Relative Index” (FERARI index) in red
plums (Prunus domestica, L., cv Nero Sardo, Dore A., Stanley) and red
grapes (Vitis vinifera, L., cv Monica and Cagnulari). In both species the
FERARI index was related to the total anthocyanins content, such variable
was determined by UV-Vis spectrophotometry and was expressed
as mg/100 g of peel of malvidin 3-glucoside, and as mg/100 g of peel of
cyanidin 3-glucoside, for grapes and plums, respectively. A good correlation
between fluorescence index and peel anthocyanins content in all
the plum cultivars was observed. On the contrary, only for one grape
cultivar (Cagnulari) was found a correlation. Moreover, FERARI index
and anthocyanins content showed a linear relationship in plums,
whereas it was logarithmic in grapes. Finally, the Multiplex 3® allowed
to detect a larger range of anthocyanins content in plums than in grape.
Preliminary results showed that the fluorimetric-based optical sensor
Multiplex 3® can be an effective tool for monitoring anthocyanins content
in the peel of red plums. Moreover, a marked difference in its use
depending on the species observed
Dore A. — L'analyse démographique de la Bourgogne au cours de la période 1954-1968
No full textA. A. Dore A. — L'analyse démographique de la Bourgogne au cours de la période 1954-1968. In: Population, 27ᵉ année, n°2, 1972. p. 328
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
