Papers by Adriana Climescu Haulica
This paper contains first of all conditions for absolute continuity as well as a new likelihood r... more This paper contains first of all conditions for absolute continuity as well as a new likelihood ratio formula for detecting a random signal whose law is unknown, and which is obscured by noise that is modeled as the output of a causal filter of weighted Wiener and Poisson processes. Secondly, the derivation presented reveals, through its reproducing kernel Hilbert space framework, the reasons that make the method work, as well as its limitations. The tools used are the Cramer-Hida representation and stochastic calculus not assuming the "usual conditions."
IEEE International Conference on Acoustics Speech and Signal Processing, 2002
In the context of stochastic dependency of the noise and signal-as in the case of the reverberati... more In the context of stochastic dependency of the noise and signal-as in the case of the reverberation noise-the classical methods of signal detection are not applicable. The paper presents a likelihood ratio detection method based on stochastic calculus. The novel aspects of the method are: the signal and the noise need not be stochastically independent and they both can be nonstationary and non-Gaussian. This method is applicable to the active sonar which is a reverberation limited system. Simulations related to the underwater propagation of the acoustic wave show a good performance of the detector at the receiver operating characteristic level. The likelihood ratio detection method can also be successfully applied in mobile communication for the channel dynamical allocation, as well as in radar applications.
We present a model of the Hypothalamo-Adreno-Pituitary (HPA) system; our approach is hierarchical... more We present a model of the Hypothalamo-Adreno-Pituitary (HPA) system; our approach is hierarchical and biologically sound, reflecting the complexity of the real HPA system. The structure of the conceptual model is based on theoretical frameworks of biological complex systems and its implementation takes advantage of recent hybrid automata modelling and analysis tools, being modular and reflecting parameter and mechanisms uncertainties.
Discrete Mathematics & Theoretical Computer Science, 2006
A classification strategy based on δ-patterns is developed via a combinatorial optimization probl... more A classification strategy based on δ-patterns is developed via a combinatorial optimization problem related with the maximal clique generation problem on a graph. The proposed solution uses the cross entropy method and has the advantage to be particularly suitable for large datasets. This study is tailored for the particularities of the genomic data.
Protocadherins are transmembrane proteins exhibiting homophilic adhesive activities through their... more Protocadherins are transmembrane proteins exhibiting homophilic adhesive activities through their extracellular domain. is Pcdh12 expressed in angiogenic endothelial cells, mesangial cells of kidney glomeruli and glycogen cells of the mouse placenta. To get insights into the role of this protein , we analyzed PCDH12-deficient mice and investigated their placental phenotype. The mice were in vivo alive and fertile, however placental and embryonic sizes were reduced compared to wild types. We observed defects in placental layer segregation and a decreased vascularization of the labyrinth associated with a reduction in cell density in this layer. To understand the molecular events responsible for the phenotypic alterations observed in placentas, we analyzed the expression profile of Pcdh12 / − − E12.5 mutant placentas in comparison with wild types, using pangenomic chips. 2,289 genes exhibited statistically significant changes in expressed levels due to loss of PCDH12. Functional grouping of modified genes was obtained by GoMiner software. Gene clusters that contained most of the differentially expressed genes were those involved in tissue morphogenesis and development, angiogenesis, cell-matrix adhesion and migration, immune response and chromatin remodeling. Our data show that loss of PCDH12 leads to morphological alterations of the placenta and to notable changes in its gene expression profile. Specific genes emerging from the microarray screen support the biological modifications observed in PCDH12-deficient placentas.
Existence et unicité de la solution de l'équation intégrale qui permet de construire explicitemen... more Existence et unicité de la solution de l'équation intégrale qui permet de construire explicitement les vraisemblances. .. . .
Studies in Classification, Data Analysis, and Knowledge Organization, 2007
Proceedings IEEE International Symposium on Information Theory,
This paper contains one application of a method that allows one to produce likelihood ratios for ... more This paper contains one application of a method that allows one to produce likelihood ratios for realistic detection problems involving random signals of unknown laws, a method that requires that only the law of the input to the filter of the noise be available.
Mathematics and Computer Science III, 2004
A method for computing the probability of symbol error for space-time trellis codes is developed ... more A method for computing the probability of symbol error for space-time trellis codes is developed by means of results from large deviation theory for quadratic Gaussian forms. The issue is that in order to build a space-time trellis code with small probability of error it is sufficient to find a metric for the Viterbi decoding algorithm for which there exists a Cramer’s rate function who minimizes a criterion on the transfer function of the trellis system. In particular, this approach gives a theoretical explanation for a simulation result of [2].
Statistics & Probability Letters, 1999
We prove a central limit theorem for products of centered i.i.d. r.v.'s ... more We prove a central limit theorem for products of centered i.i.d. r.v.'s taking values on nilpotent, graded, simply connected Lie groups. The main tool is given by weak approximation results for SDEs.
Physiological Genomics, 2008
Protocadherins are transmembrane proteins exhibiting homophilic adhesive activities through their... more Protocadherins are transmembrane proteins exhibiting homophilic adhesive activities through their extracellular domain. Protocadherin 12 ( Pcdh12) is expressed in angiogenic endothelial cells, mesangial cells of kidney glomeruli, and glycogen cells of the mouse placenta. To get insight into the role of this protein in vivo, we analyzed PCDH12-deficient mice and investigated their placental phenotype. The mice were alive and fertile; however, placental and embryonic sizes were reduced compared with wild-type mice. We observed defects in placental layer segregation and a decreased vascularization of the labyrinth associated with a reduction in cell density in this layer. To understand the molecular events responsible for the phenotypic alterations observed in Pcdh12−/− placentas, we analyzed the expression profile of embryonic day 12.5 mutant placentas compared with wild-type placentas, using pangenomic chips: 2,289 genes exhibited statistically significant changes in expressed levels...
Fractals, 1993
Several nonlinear stochastic differential equations have been proposed in connection with self-or... more Several nonlinear stochastic differential equations have been proposed in connection with self-organized critical phenomena. Due to the threshold condition involved in its dynamic evolution, an infinite number of nonlinearities arise in a hydrodynamic description. We study two models with different noise correlations which make all nonlinear contributions to be equally relevant below the upper critical dimension. The asymptotic values of the critical exponents are estimated from a systematic expansion in the number of coupling constants by means of the dynamic renormalization group.
Background: This work explores the quantitative characteristics of the local transcriptional regu... more Background: This work explores the quantitative characteristics of the local transcriptional regulatory network based on the availability of time dependent gene expression data sets. The dynamics of the gene expression level are fitted via a stochastic differential equation model, yielding a set of specific regulators and their contribution. Results: We show that a beta sigmoid function that keeps track of temporal parameters is a novel prototype of a regulatory function, with the effect of improving the performance of the profile prediction. The stochastic differential equation model follows well the dynamic of the gene expression levels. Conclusion: When adapted to biological hypotheses and combined with a promoter analysis, the method proposed here leads to improved models of the transcriptional regulatory networks.
BMC Bioinformatics, 2007
Background: This work explores the quantitative characteristics of the local transcriptional regu... more Background: This work explores the quantitative characteristics of the local transcriptional regulatory network based on the availability of time dependent gene expression data sets. The dynamics of the gene expression level are fitted via a stochastic differential equation model, yielding a set of specific regulators and their contribution. Results: We show that a beta sigmoid function that keeps track of temporal parameters is a novel prototype of a regulatory function, with the effect of improving the performance of the profile prediction. The stochastic differential equation model follows well the dynamic of the gene expression levels. Conclusion: When adapted to biological hypotheses and combined with a promoter analysis, the method proposed here leads to improved models of the transcriptional regulatory networks.
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Papers by Adriana Climescu Haulica