Institute of Mathematics and Informatics

Семинар по изследване на операциите
2024-06-11 14:00 - 15:30 (Europe/Sofia) | Институт по математика и информатика – БАН, Block 8, 1113 БАН IV км., София, Bulgaria
На 11-ти юни (вторник) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
Mathematical modelling of torque-velocity and torque-angle relationships
ще изнесе проф. Петър Миланов, ИМИ-БАН и ЮЗУ.

Семинар по изследване на операциите
2024-06-18 14:00 - 15:30
На 18-ти юни (вторник) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
Mathematical modelling of torque-velocity and torque-angle relationships – part 2: numerical results
ще изнесе проф. Петър Миланов, ИМИ-БАН и ЮЗУ.

Семинар по изследване на операциите
2024-07-02 14:00 - 15:30
На 2-ри юли (вторник) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
On some contemporary mathematical methods for data analysis
ще изнесе проф. Пандо Георгиев, ИМИ-БАН.
Абстракт:

We will review some selected methods and algorithms for data analysis:
A) Latent component analysis – reveals hidden features of composite data. Particularly, we will describe some
Signal Separation Methods:

based on statistical independence – Independent Component Analysis
based on sparsity. – Sparse Component Analysis
based on non-negativity – Non-Negative Matrix and Tensor Factorization

B) New approach to multiclass learning problems and applications to some problems in machine learning, as:

nonlinear least square problems
subspace clustering and non-linear skeletons
reconstruction of several functions from mixed samples
support vector kernel regression (under development)

C) kernel methods for data analysis
D) tensor decompositions and tensor networks.
Some of the above topics are interconnected and subject to intensive development with numerous applications.

Семинар по изследване на операциите
2024-10-01 14:00 - 15:30
На 1 октомври (вторник) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
Graphs as an universal modeling tool
ще изнесе проф. Никола Янев, ИМИ-БАН.
Абстракт: For a series of practical optimization problems, we show that formulating them as graph optimization problems enables the development of competitive algorithms. The problems considered are known as: protein threading problem, contact map overlap, HP folding, a new scheduling theory problem, classification problem and the biclustering problem. The focus is on formulating them as graph optimization problems, which are solved by using Integer programming techniques.

Семинар по изследване на операциите
2024-10-09 14:00 - 15:30
На 9 октомври (сряда) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
Graphs as an universal modeling tool, част 2
ще изнесе проф. Никола Янев, ИМИ-БАН.
Абстракт: For a series of practical optimization problems, we show that formulating them as graph optimization problems enables the development of competitive algorithms. The problems considered are known as: protein threading problem, contact map overlap, HP folding, a new scheduling theory problem, classification problem and the biclustering problem. The focus is on formulating them as graph optimization problems, which are solved by using Integer programming techniques.

Семинар по изследване на операциите
2024-10-15 14:00 - 15:30
На 15 октомври (вторник) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
Asymptotic covariance matrix of Capon’s Maximum likelihood estimator and application of steered response power phase alignment algorithm in seismic array data processing
ще изнесе Александр Варипаев от секция ИОСВ.
Абстракт: Capon’s estimator was originally developed for frequency-wavenumber power spectral density analysis. Theoretically, it can be treated as maximum likelihood estimator of unknown vector parameter of multidimensional linear system (MLS) model with one input and m outputs. Practically important and non-trivial case is considered, when the number of nuisance parameters, which are values of input deterministic signal, tends to infinity. Under assumptions that MLS output signals distorted by random Gaussian stationary EMBED Equation.DSMT4 -dimensional noise with known matrix power spectrum and the likelihood function of observations satisfies the conditions of local asymptotic normality, the analytical form of limiting covariance matrix of the Capon’s estimate is given.Steered response power phase alignment algorithm (SRP-PHAT) is devoted to subclass of so called phase-based robust estimators. Mathematical basis of SRP-PHAT estimator shows its applicability to small-aperture seismic array data to solve two different tasks: frequency-wavenumber analyses and seismic source localization problems. Several experiments with real data demonstrate its advantage compared to conventional methods that are involved in most of free and commercial seismological software.

Семинар по изследване на операциите
2024-10-22 14:00 - 15:30
На 22 октомври (вторник) от 14:00 ч. в зала 503 на ИМИ ще се състои сбирка на
Семинара по Изследване на операциите.
Доклад на тема
Asymptotic covariance matrix of Capon’s Maximum likelihood estimator and application of steered response power phase alignment algorithm in seismic array data processing – част 2
ще изнесе Александр Варипаев от секция ИОСВ.

Абстракт: Capon’s estimator was originally developed for frequency-wavenumber power spectral density analysis. Theoretically, it can be treated as maximum likelihood estimator of unknown vector parameter of multidimensional linear system (MLS) model with one input and m outputs. Practically important and non-trivial case is considered, when the number of nuisance parameters, which are values of input deterministic signal, tends to infinity. Under assumptions that MLS output signals distorted by random Gaussian stationary EMBED Equation.DSMT4 -dimensional noise with known matrix power spectrum and the likelihood function of observations satisfies the conditions of local asymptotic normality, the analytical form of limiting covariance matrix of the Capon’s estimate is given.Steered response power phase alignment algorithm (SRP-PHAT) is devoted to subclass of so called phase-based robust estimators. Mathematical basis of SRP-PHAT estimator shows its applicability to small-aperture seismic array data to solve two different tasks: frequency-wavenumber analyses and seismic source localization problems. Several experiments with real data demonstrate its advantage compared to conventional methods that are involved in most of free and commercial seismological software.
