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Search Results: 1 - 10 of 31047 matches for " Z. Ristic "
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Robust Stereo-Vision Based 3D Object Reconstruction for the Assistive Robot FRIEND
RISTIC-DURRANT, D.,GRIGORESCU, S. M.,GRASER, A.,COJBASIC, Z.
Advances in Electrical and Computer Engineering , 2011, DOI: 10.4316/aece.2011.04003
Abstract: A key requirement of assistive robot vision is the robust 3D object reconstruction in complex environments for reliable autonomous object manipulation. In this paper the idea is presented of achieving high robustness of a complete robot vision system against external influences such as variable illumination by including feedback control of the object segmentation in stereo images. The approach used is to change the segmentation parameters in closed-loop so that object features extraction is driven to a desired result. Reliable feature extraction is necessary to fully exploit a neuro-fuzzy classifier which is the core of the proposed 2D object recognition method, predecessor of 3D object reconstruction. Experimental results on the rehabilitation assistive robotic system FRIEND demonstrate the effectiveness of the proposed method.
In-situ Investigation of the Early Stage of TiO2 epitaxy on (001) SrTiO3
M. Radovic,M. Salluzzo,Z. Ristic,R. Di Capua,N. Lampis,R. Vaglio,F. Miletto Granozio
Physics , 2011, DOI: 10.1063/1.3613637
Abstract: We report on a systematic study of the growth of epitaxial TiO2 films deposited by pulsed laser deposition on Ti-terminated (001) SrTiO3 single crystals. By using in-situ reflection high energy electron diffraction, low energy electron diffraction, x-ray photoemission spectroscopy and scanning probe microscopy, we show that the stabilization of the anatase (001) phase is preceded by the growth of a pseudomorphic Sr-Ti-O intermediate layer, with a thickness between 2 and 4 nm. The data demonstrate that the formation of this phase is related to the activation of long range Sr migration from the substrate to the film. The role of interface Gibbs energy minimization, as a driving force for Sr diffusion, is discussed. Our results enrich the phase diagram of the Sr-Ti-O system under epitaxial strain opening the roudeficient SrTiO phase.
Hidden Semi-Markov Models for Single-Molecule Conformational Dynamics
A. Kovalev,N. Zarrabi,F. Werz,M. Boersch,Z. Ristic,H. Lill,D. Bald,C. Tietz,J. Wrachtrup
Quantitative Biology , 2009,
Abstract: The conformational kinetics of enzymes can be reliably revealed when they are governed by Markovian dynamics. Hidden Markov Models (HMMs) are appropriate especially in the case of conformational states that are hardly distinguishable. However, the evolution of the conformational states of proteins mostly shows non-Markovian behavior, recognizable by non-monoexponential state dwell time histograms. The application of a Hidden Markov Model technique to a cyclic system demonstrating semi-Markovian dynamics is presented in this paper and the required extension of the model design is discussed. As standard ranking criteria of models cannot deal with these systems properly, a new approach is proposed considering the shape of the dwell time histograms. We observed the rotational kinetics of a single F1-ATPase alpha3beta3gamma sub-complex over six orders of magnitude of different ATP to ADP and Pi concentration ratios, and established a general model describing the kinetics for the entire range of concentrations. The HMM extension described here is applicable in general to the accurate analysis of protein dynamics.
FISKALNO UPRAVLJANJE - FISCAL MANAGEMENT
Zarko Ristic, Kristijan Ristic, Ljubomir Miljkovic
FBIM Transactions , 2015, DOI: 10.12709/fbim.03.03.02.13
Abstract: Fiscal finances within macroeconomic theory include global and waist tour options collection (mobilization), the distribution and allocation of limi polled financial resources of the state and its political- territorial collectivity on al of the alternative uses of the expected (programmed) yields (effects) investment funds in the process of covering the costs of financing social activities and social standards, and alimentation public needs and public sector development. Modern theories of fiscal management formulate criteria decision-making publicly financed investment decisions in the sphere of public functions of the state and its entities, which include issues (a) who, what and how much investment should amount to determine how quickly the public sector has to grow (b) when and how the fiscal investment be fund to determine the preferred tax and budget structure, and (c) what sort of structure (and volume) of budgetary investment should be to find out in which segment of the public spending growing or decreasing effects (yield) from the point of quacktures of public services , efficiency of public needs and rationality of public spending. These are precisely the goals of fiscal management that optimize decisions on the mobilization and allocation of financial resources to the principle of maximizing the profitability of the public sector and minimizing the cost of public alimentation needs, while maintaining a satisfactory level of liquidity of the country (without falling into deficit) and increase the efficiency of tax policy and rationality budgetary policy.
Modelling and Performance Analysis of a Network of Chemical Sensors with Dynamic Collaboration
Alex Skvortsov,Branko Ristic
International Journal of Distributed Sensor Networks , 2012, DOI: 10.1155/2012/656231
Abstract: The problem of environmental monitoring using a wireless network of chemical sensors with a limited energy supply is considered. Since the conventional chemical sensors in active mode consume vast amounts of energy, an optimisation problem arises in the context of a balance between the energy consumption and the detection capabilities of such a network. A protocol based on “dynamic sensor collaboration” is employed: in the absence of any pollutant, the majority of sensors are in the sleep (passive) mode; a sensor is invoked (activated) by wake-up messages from its neighbors only when more information is required. The paper proposes a mathematical model of a network of chemical sensors using this protocol. The model provides valuable insights into the network behavior and near optimal capacity design (energy consumption against detection). An analytical model of the environment, using turbulent mixing to capture chaotic fluctuations, intermittency, and nonhomogeneity of the pollutant distribution, is employed in the study. A binary model of a chemical sensor is assumed (a device with threshold detection). The outcome of the study is a set of simple analytical tools for sensor network design, optimisation, and performance analysis.
Electrophysiological Evidence for Spatiotemporal Flexibility in the Ventrolateral Attention Network
Jelena Ristic, Barry Giesbrecht
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024436
Abstract: Successful completion of many everyday tasks depends on interactions between voluntary attention, which acts to maintain current goals, and reflexive attention, which enables responding to unexpected events by interrupting the current focus of attention. Past studies, which have mostly examined each attentional mechanism in isolation, indicate that volitional and reflexive orienting depend on two functionally specialized cortical networks in the human brain. Here we investigated how the interplay between these two cortical networks affects sensory processing and the resulting overt behavior. By combining measurements of human performance and electrocortical recordings with a novel analytical technique for estimating spatiotemporal activity in the human cortex, we found that the subregions that comprise the reflexive ventrolateral attention network dissociate both spatially and temporally as a function of the nature of the sensory information and current task demands. Moreover, we found that together with the magnitude of the early sensory gain, the spatiotemporal neural dynamics accounted for the high amount of the variance in the behavioral data. Collectively these data support the conclusion that the ventrolateral attention network is recruited flexibly to support complex behaviors.
THE INFLUENCE OF SMOKING ON THE LUNG FUNCTION PARAMETERS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)
Veroljub Vucic,Lidija Ristic
Acta Medica Medianae , 2005,
Abstract: Chronic obstructive pulmonary disease (COPD) has the prevalence of 6-14% in the whole population. COPD is the forth most common cause of death worldwide. It is expected to become the third most common cause by the year 2020. Tobacco smoke, the most important environmental risk factor for the development of COPD, is a mixture of more than 4000 different compounds, many of which are carcinogenic or irritative. Tobacco has been shown to cause about twenty five life-threatening diseases or groups of diseases, many of which can be prevented, delayed or mitigated by smoking cessation. Unfortunately, the number of smokers is still increasing in many developing and developed countries, especially among females. If only small portion of today’ s 1,1 billion smokers were able to stop smoking, long-term health and economic benefits would be immense. According to this data, the authors set the goal to investigate the parameters of lung function in patients with COPD, who are smokers and non-smokers. The retrospective randomized diagnostic study enrolled 60 patients (36 m. and 24 f.) treated ambulatory during exacerbations of COPD, being divided in two groups - 30 smokers and 30 non-smokers. The resulting spirometric parameters of lung function (FEV1/FVC, FEV1, FVC), according to GOLD criteria, were analyzed. Smokers with COPD have statistically significant decline of the parameters than non- smokers with COPD. Smokers who smoke less than 10 years have significantly better FEV1/FVC, FEV1 and FVC than smokers who smoke for more than 20 years. It may be concluded that smoking as a risk factor significantly influences the impairment of the lung function parameters, proportionally to the duration of smoking history compared to non-smokers. Patients with COPD should be encouraged to stop smoking, which significantly increases the survival rate, even in patients with very low value of FEV1.
Modelling and Performance analysis of a Network of Chemical Sensors with Dynamic Collaboration
Alex Skvortsov,Branko Ristic
Computer Science , 2011,
Abstract: The problem of environmental monitoring using a wireless network of chemical sensors with a limited energy supply is considered. Since the conventional chemical sensors in active mode consume vast amounts of energy, an optimisation problem arises in the context of a balance between the energy consumption and the detection capabilities of such a network. A protocol based on "dynamic sensor collaboration" is employed: in the absence of any pollutant, majority of sensors are in the sleep (passive) mode; a sensor is invoked (activated) by wake-up messages from its neighbors only when more information is required. The paper proposes a mathematical model of a network of chemical sensors using this protocol. The model provides valuable insights into the network behavior and near optimal capacity design (energy consumption against detection). An analytical model of the environment, using turbulent mixing to capture chaotic fluctuations, intermittency and non-homogeneity of the pollutant distribution, is employed in the study. A binary model of a chemical sensor is assumed (a device with threshold detection). The outcome of the study is a set of simple analytical tools for sensor network design, optimisation, and performance analysis.
Monitoring and prediction of an epidemic outbreak using syndromic observations
Alex Skvortsov,Branko Ristic
Quantitative Biology , 2011,
Abstract: The paper presents an algorithm for syndromic surveillance of an epidemic outbreak formulated in the context of stochastic nonlinear filtering. The dynamics of the epidemic is modeled using a generalized compartmental epidemiological model with inhomogeneous mixing. The syndromic (typically non-medical) observations of the number of infected people (e.g. visits to pharmacies, sale of certain products, absenteeism from work/study etc.) are used for estimation. The state of the epidemic, including the number of infected people and the unknown parameters of the model, are estimated via a particle filter. The numerical results indicate that the proposed framework can provide useful early prediction of the epidemic peak if the uncertainty in prior knowledge of model parameters is not excessive.
Analysis of prognostic factors for overall survival in patients with advanced non-small cell lung cancer treated with second line chemotherapy  [PDF]
Milan Rancic, Lidija Ristic, Marina Cekic, Tatjana Pejcic
Advances in Lung Cancer (ALC) , 2013, DOI: 10.4236/alc.2013.23007
Abstract:

Aim: The aim of this study was to investigate prognostic factors for survival in patients with advanced NSCLC who receiving second-line chemotherapy. Methods: We retrospectively reviewed data of 116 patients with NSCLC receiving second-line treatments from October 2010 to December 2012 in Clinic for Lung Diseases of Clinical center Nis, Department for Pulmonary Oncology. Thirteen potential prognostic factors were chosen for analysis. Univariate analysis was conducted to identify prognostic factors associated with progression free survival and overall survival. Multivariate analysis included the prognostic significance factors in univariate analysis. Results: The univariate analysis for progression free survival (PFS) and overall survival (OS) was identified to have prognostic significance: performance status, smoking, weight loss, comorbidity, number of meta localization, first-line chemotherapy regimen and response to first-line chemotherapy. Nevertheless, multivariate Cox prortional hazard regression analysis showed that performance status (PFS: p = 0.000, OS: p = 0.000) weight loss ≥ 5% (PFS: p = 0.000, OS: p = 0.002), comorbidity (PFS: p = 0.001, OS: p = 0.012) and four places of meta localization (PFS: p = 0.021, OS: p = 0.021) were considered independent prognostic factors for both, progression free survival and overall survival. Conclusion: Performance status, weight loss ≥ 5%, comorbidity and higher number of meta localization were identified as prognostic factors for survival in advanced NSCLC patients receiving second-line chemotherapy treatment. These findings may help pretreatment prediction of survival and may facilitate in the future integration new agents into second-line treatment.

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