6,053 research outputs found
Which role for an ontology of uncertainty?
No full textAn Ontology of Uncertainty, like the one proposed by the W3C’s UR3W-XG incubator group, provides a vocabulary to annotate
different sources of information with different types of uncertainty. Here
we argue that such annotations should be clearly mapped to corresponding reasoning and representation strategies. This mapping allows the system to analyse the information on the basis of its uncertainty model,
running the inference proccess according to the respective uncertainty.
As a proof of concepts we present a data integration system implementing a semantics-aware matching strategy based on an ontological representation of the uncertain/inconsistent matching relations generated by the various matching operators. In this scenario the sources of information
to be analyzed according to different uncertainty models are independent
and no intersection among them is to be managed. This particular case allows a straight-forward use of the Ontology of Uncertainty to drive the reasoning process, although in general the assumption of independence among the source of information is a lucky case. This position paper
highlights the need of additional work on the Ontology of Uncertainty in order to support reasoning processes when combinations of uncertainty models are to be applied on a single source of information
Localization and tracking of mobile antenna in urban environment
No full textIn mobile communication, many new services rely on the knowledge of mobile terminals location.
Mobile units location estimate is aimed at using the cellular network infrastructure and protocols to provide a reliable and accurate estimate of mobile terminals positions without the need for global
positioning systems such as GPS. In this paper a lookup table correlation techniques with multiple position estimation and optimal location is presented. The approach is based on advanced propagation models, designed for planning of mobile radio networks and on information that can be extracted from a GIS map of the interested
area in conjunction with Kalman prevision
filtering to improve precision in location and tracking
Open source electromagnetic field monitoring as e-government service
No full textDeployment of new mobile telecommunication
services is causing a fast growth of the number of transmission stations installed in our environment, possibly resulting in an increased risk to human health. In the framework of planning transmission equipment deployment, a careful management of
electromagnetic and acoustical impact is of
paramount importance, as well as environmentconscious disposal of waste. This paper proposes the Open Source electromagnetic Field Monitor (OSE-FM), an innovative e-Government service for computing electromagnetic field levels.
OSEFM focuses on the integration of Open source WebGIS components, and on the implementation of advanced models for the approximate calculation of the Electromagnetic Field
A toward framework for generic uncertainty management
No full textThe need for an automatic inference process able to deal with information coming from unreliable sources is becoming a relevant issue both on corporate networks and on the open Web.
Mathematical theories to reason with uncertain information have been successfully applied in several situations, but each one of these models is tailored to deal with a specific semantics of uncertainty.
In this paper, we put forward the idea of using explicit representations of the different types of uncertainty for partitioning the inference process into parts. By coordinating multiple independent reasoning processes, we are sometimes able to apply a specific model to each type of uncertain information, and recombine the final results via a suitable reconciliation process.
We validated our approach applying it to the classic schema matching problem, and using the Ontology Alignment Evaluation Initiative, (OAEI) tests to assess the results
Author Guidelines
No full textReproduction Rights Universitas Scientiarum is licensed under Creative Commons: Attribution - Noncommercial - No derivative works, 2.5 of Colombia. Consequently, it can be electronically reproduced, distributed and publically communicated, provided the authors and the Pontificia Universidad Javeriana are acknowledged. Commercial use of this work is not permitted. Modifications to the original work, and distribution of modified copies are prohibited. Upon acceptance of the article, the author will send the journal’s Office a printed and signed license of economic rights transfer, which authorizes its reproduction in Universitas Scientiarum (the license can be downloaded from the journal website; http://revistas.javeriana.edu.co/scientarium/web; http://revistas.javeriana.edu.co/scientarium/ojs). Such permission will infer the author’s acceptance of the article’s dissemination not only on paper but also in electronic media, that is, in websites and in national and international bibliographic databases. The magazine accepts pre-print articles, previously uploaded to e-print servers (OAI - such as arxiv.org)
Treatment intensification of malignant lymphomas with autologous bone marrow transplantation and granulocyte colony stimulating factor
No full textTreatment intensification with autologous bone marrow transplantation (ABMT) was administered to 37 cases of Hodgkin's and non-Hodgkin's lymphoma (HL and NHL) who were in complete or partial remission (CR or PR) after chemotherapy (MOPP/ABVD or F-MACHOP respectively) and to 12 cases of HL and NHL who were in relapse. ABMT treatment was BAVC for NHL and BEAM for HL. Marrow cells were harvested from the marrow and cryopreserved. The number of mononuclear marrow cells that was reinfused ranged between 0.19 and 0.80 x 108/Kg b.w. (median 0.39). All the patients were treated with granulocyte colony stimulating factor (G-CSF, Filgrastim) at a dose of 5 mg/Kg b.w. from day +4 until the absolute neutrophil count exceeded 1 x109/L for 3 consecutive days. Engraftment was observed in all cases, and no transplant-related deaths occurred. The patients with NHL and HL received a median of 12 (range 2-19) and 14.5 (range 9-27) doses of G-CSF respectively. Median time to 20 x 109/L platelet count was 14 to 17 days. Median time to an absolute neutrophil count 0.5x109/L was 13 days. A febrile episode during the period of post-transplant aplasia was documented in 35 patients (71%). Fever was associated with Gram+ bacteraemia in 31% of the cases and with Gram- bacteraemia in 11% of cases. Herpes Simplex infection was documented in two cases. No fungal infections were recorded. Median hospitalisation time from reinfusion ranged between 19.5 days (NHL) and 23 days (HL). Thirty-four of 37 cases (92%) who were transplanted in CR or in PR are currently alive and in continuous CR with a median follow-up time of 37 months after ABMT. Three of 12 cases (25%) who were transplanted in relapse are alive and in CR. Our data point out that ABMT followed by G-CSF is a safe and a very effective procedure for high risk malignant lymphomas, when ABMT is planned and is performed not as a rescue procedure but when it is integrated in the treatment strategy from the very beginning
Estimation in threshold autoregressive models with a stationary and a unit root regime
No full textThis paper treats estimation in a class of new nonlinear threshold autoregressive models with both a stationary and a unit root regime. Existing literature on nonstationary threshold models have basically focused on models where the nonstationarity can be removed by differencing and/or where the threshold variable is stationary. This is not the case for the process we consider, and nonstandard estimation problems are the result. This paper proposes a parameter estimation method for such nonlinear threshold autoregressive models using the theory of null recurrent Markov chains. Under certain assumptions, we show that the ordinary least squares (OLS) estimators of the parameters involved are asymptotically consistent. Furthermore, it can be shown that the OLS estimator of the coefficient parameter involved in the stationary regime can still be asymptotically normal while the OLS estimator of the coefficient parameter involved in the nonstationary regime has a nonstandard asymptotic distribution. In the limit, the rate of convergence in the stationary regime is asymptotically proportional to n-1/4, whereas it is n-1 in the nonstationary regime. The proposed theory and estimation method are illustrated by both simulated data and a real data example.Autoregressive process; null-recurrent process; semiparametric model; threshold time series; unit root structure.
Interpreting null findings from trials of alcohol brief interventions
No full textThe effectiveness of alcohol brief intervention (ABI) has been established by a succession of meta-analyses but, because the effects of ABI are small, null findings from randomized controlled trials are often reported and can sometimes lead to skepticism regarding the benefits of ABI in routine practice. This article first explains why null findings are likely to occur under null hypothesis significance testing (NHST) due to the phenomenon known as ‘the dance of the p-values’. A number of misconceptions about null findings are then described, using as an example the way in which the results of the primary care arm of a recent cluster randomized trial of ABI in England (the SIPS project) have been misunderstood. These misinterpretations include the fallacy of ‘proving the null hypothesis’ that lack of a significant difference between the means of sample groups can be taken as evidence of no difference between their population means, and the possible effects of this and related misunderstandings of the SIPS findings are examined. The mistaken inference that reductions in alcohol consumption seen in control groups from baseline to follow-up are evidence of real effects of control group procedures is then discussed and other possible reasons for such reductions, including regression to the mean, research participation effects, historical trends, and assessment reactivity, are described. From the standpoint of scientific progress, the chief problem about null findings under the conventional NHST approach is that it is not possible to distinguish ‘evidence of absence’ from ‘absence of evidence’. By contrast, under a Bayesian approach, such a distinction is possible and it is explained how this approach could classify ABIs in particular settings or among particular populations as either truly ineffective or as of unknown effectiveness, thus accelerating progress in the field of ABI research
A general approach to securely querying XML
No full textAccess control models for XML data can be classified in two major categories: node filtering and query rewriting systems. The first category includes approaches that use access policies to compute secure user views on XML data sets. User queries are then evaluated on those views. In the second category of approaches, authorization rules are used to transform user queries to be evaluated against the original XML dataset. The aim of this paper is to describe a model
combining the advantages of these approaches and overcoming their limitations.
The model specification is given using a Finite State Automata, ensuring generality
and easiness of standardization w.r.t. specific implementation techniques
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