Artur Gramacki

Artur Gramacki
University of Zielona Góra | UZ

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60
Publications
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229
Citations

Publications

Publications (60)
Chapter
The automatic detection of nuclei within cytological samples is crucial for quantitative analysis in medical applications. Fortunately, modern digital microscopy systems allow imaging of biological material with very high accuracy. A typical cytological sample contains hundreds or thousands of cell nuclei that need to be examined for a particular t...
Chapter
This chapter is devoted to presentation of the results of author’s own research on fast computation of kernel density estimators and bandwidth selection. The developed methods are based on the fast Fourier transform (FFT) algorithm that relies on a preliminary data transformation known as data binning. We start with the description of binning rules...
Chapter
This chapter is a concise summary of the author’s own contributions described in the book in relation to the most recent research in nonparametric smoothing methods. Also, a number of open problems regarding nonparametric smoothing have been pointed out.
Chapter
This chapter describes the most popular bandwidth selection methods (also known as bandwidth selectors). It starts with a description of the constrained and unconstrained bandwidth selectors and moves on to an overview of the three major types of selectors (that is: rule-of-thumb (ROT), cross-validation (CV) and plug-in (PI) selectors). The next pa...
Chapter
This chapter discusses author’s own research related to fast computation using the univariate plug-in algorithm, a type of a bandwidth selection algorithm. In contrast to the results presented in Chapter 5, this chapter describes a hardware-based method, which relies on utilizing the so-called field-programmable gate arrays (FPGA). FPGA devices are...
Chapter
This presents a number of applications related to KDE. The first one is discriminant analysis, a well-known data exploration method. The second is cluster analysis (this is also a well-researched field), where the so-called mean-shift algorithm is used. We illustrate the two areas with some simple numerical examples confirming the practical usabili...
Chapter
This chapter describes the kernel density estimation technique that can be considered a smoothed version of the Parzen windows presented in the Chapter 2. First, the most popular kernel types are presented together with a number of basic definitions both for uni- and multivariate cases and then a review of performance criteria is provided, starting...
Chapter
This chapter presents a background material, describing the fundamental concepts related to the nonparametric density estimation. First, a well-known histogram technique is briefly presented together with a description of its main drawbacks. To avoid the highlighted problems, at least to some extent, one might use a smart histogram modification kno...
Conference Paper
Multivariate kernel density estimation (KDE) is a very important statistical technique in exploratory data analysis. Research on high performance KDE is still an open research problem. One of the most elegant and efficient approach utilizes the Fast Fourier Transform. Unfortunately, the existing FFT-based solution suffers from a serious limitation,...
Article
There are two main computational problems related to the kernel density estimation (KDE): (a) fast evaluating of the kernel density estimates, (b) fast estimating of the optimal bandwidth. Progress towards the latter problem has been relatively slow. The high computational cost required for direct bandwidth estimation provides great motivation for...
Article
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The problem of fast computation of multivariate density estimation is still an open research problem. In our view, the existing solutions don't resolve this matter in a satisfactory way. One of the most elegant and efficient approach utilizes fast Fourier transform. Unfortunately, the existing FFT-based solution suffers a serious bottleneck, as it...
Article
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Approximate query processing (AQP) is an interesting alternative for exact query processing. It is a tool for dealing with the huge data volumes where response time is more important than perfect accuracy (this is typically the case during initial phase of data exploration). There are many techniques for AQP, one of them is based on probability den...
Article
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FPGA technology can offer significantly higher performance at much lower power than is available from CPUs and GPUs in many computational problems. Unfortunately, programming for FPGA (using hardware description languages, HDL) is a difficult and not-trivial task and is not intuitive for C/C++/Java programmers. To bring the gap between programming...
Article
This paper reports further development of the so-called ID Lyapunov equation based approach to the stability analysis of differential linear repetitive processes. In particular, it is shown that this approach leads to stability tests which can be implemented by computations with matrices which have constant entries, and that if the example under co...
Article
The Probability Density Function (PDF) is a key concept in statistics. Constructing the most adequate PDF from the observed data is still an important and interesting scientific problem, especially for large datasets. PDFs are often estimated using nonparametric data-driven methods. One of the most popular nonparametric method is the Kernel Density...
Article
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The study included 249 horses belonging to three horse breeds. Konik horses, comprising the first group, are an example of breed similar to the extinct Tarpan. In our study, these horses were taken to be a primitive anatomical model of the horse body. The other groups comprised the Polish Half-bred horse and the Thoroughbred horse. The biometric ch...
Article
Full-text available
Abstrakt. Artykuł pokazuje przykładowe zastosowanie architektury CUDA opracowanej przez firmę NVIDIA dla swoich kart graficznych. CUDA to uniwersalna architektura procesorów wielordzeniowych instalowanych we współczesnych, najbardziej wydajnych, kartach graficznych. Karta taka, oprócz oczywistych zastosowań w dziedzinie ogólnie pojętego przetwarzan...
Conference Paper
Full-text available
In the paper a Java based toolbox has been presented. It is used in teaching of a special case of nD systems -Linear Repetitive Processes (LRP). Its predecessor has been developed in the Matlab environment so to use it a Matlab licence is necessary. This restriction has been removed after making it available in the Internet as a Java based program....
Article
Full-text available
Discrete linear repetitive processes are a distinct class of two-dimensional (2-D) linear systems with applications in areas ranging from long-wall coal cutting through to iterative learning control schemes. The feature which makes them distinct from other classes of 2-D linear systems is that information propagation in one of the two independent d...
Article
.Differential linear repetitive processes are a distinct class of 2D linear systems which pose problems which cannot (except in a few very restrictive special cases) be solved by application of existing linear systems theory, and hence by the use of many of the currently available tools for computer aided analysis and simulation. One such problem a...
Article
Repetitive processes are a distinct class of 2-D systems of both practical and algorithmic interest. The paper gives some important new results on the analysis and control of the sub-class known as discrete linear repetitive processes in the presence of a general set of pass initial conditions, which are termed boundary conditions here. These resul...
Conference Paper
Differential linear repetitive processes are a distinct sub-class of 2D continuous-discrete linear systems which pose problems that cannot (except in a few very restrictive special cases) be solved by the direct application of standard (1D) systems theory and hence by the direct use of a large number of currently-available tools for computer-aided...
Conference Paper
Linear repetitive processes are a distinct class of 2D linear systems of both theoretical and practical interest. The stability theory for these processes currently consists of two distinct concepts termed asymptotic stability and stability along the pass respectively where the former is a necessary condition for the latter. Recently applications h...
Article
Full-text available
Differential linear repetitive processes are a distinct class of two-dimensional linear systems which can be used, for example, to model industrial processes such as long-wall coal cutting operations. Also, they can be used to study key properties of classes of linear iterative learning schemes. The key feature of interest in the paper is the fact...
Article
The essential unique characteristic of a repetitive, or multipass, process is a series of passes through a set of dynamics defined over a fixed finite duration termed the pass length. The key feature of interest is the fact that the information propagation in one of the two separate directions evolves continuously over a finite fixed interval while...
Article
In the paper, 2-D elementary operations and some other algebraic techniques are employed to construct a number of Roesser type state-space realizations of 2-D MIMO linear systems. The main result consists of deriving various such models for a prescribed transfer function matrix which is a two variable rational matrix.
Article
Differential linear repetitive processes are a class of linear systems which can be used, for example, to model industrial processes such as long-wall coal cutting operations. The key feature of interest in this paper is the fact that information propagation in one of the two separate directions in such processes evolves continuously over a finite...
Conference Paper
Repetitive, or multipass, processes are a class of 2D systems of both practical and algorithmic/theoretical interest whose dynamics cannot be analysed or controlled using standard (1D) systems theory. Recently it has been shown that the modelling of the boundary conditions, also known as the process initial conditions, is a crucial feature in the a...
Conference Paper
Repetitive processes are a distinct class of 2D systems of both theoretic and practical interest. For example, they arise in the study of industrial processes such as long-wall coal cutting operations and also in the modeling of classes of iterative learning control schemes. This paper describes the development of MATLAB based tools for control rel...
Conference Paper
This paper presents methods for constructing discrete approximations to the dynamics of differential linear repetitive processes which are a distinct class of 2D linear systems. Previous work has shown that `classical' discretization methods, such as the trapezoidal rule, can be adapted for application to differential linear repetitive processes, b...
Article
In this paper so-called multitime scale systems are described in terms of discrete repetitive processes which belong to the wide family of so-called 2D systems.
Article
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Abstrakt. W artykule omówiono udostępniony w połowie 2006 roku przez firmę Oracle nowy, niezaleŜnie sprzedawany, produkt o nazwie Secure Enterprise Search (SES). Zastępuje on znany od dłuŜszego czasu moduł Ultra Search (US) dołączany bezpłatnie do wersjach 9i oraz 10g serwera bazodanowego Oracle. SES, w odróŜnieniu od US, stanowi niezaleŜny produkt...
Article
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Abstrakt. Projekt R jest obecnie jednym z najdynamiczniej rozwijających się pakietów statystycznych udostępnianych na zasadach licencji GNU GPL. Prekompilowane wersje R dostępne są na platformach Windows, Macintosh i różnych wersjach Linuksa. Może on śmiało konkurować z komercyjnymi pakietami statystycznymi, takimi np. jak Statistica, SPSS, Matlab...
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Abstrakt. Przeszukiwanie dużych zbiorów dokumentów (dających się w ogólności sprowadzić do postaci tekstowej) odbywa się najczęściej w ten sposób, że użytkownik formułuje zapytanie wpisując słowa kluczowe i/lub frazy, które w jego odczuciu najlepiej opisują poszukiwane w dokumentach treści. Następnie obsługujące te zapytania wyszukiwarki zwracają p...
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Abstrakt. W praktyce często okazuje się, że duża ilość posiadanych danych wcale nie musi iść w parze z łatwością ich analizowania i, co ważniejsze, wyciągania na ich podstawie wartościowych i użytecznych wniosków. Mówiąc o dużych ilościach danych mamy na myśli, mówiąc w języku bazodanowym, zarówno dużą liczbę rekordów, jak i dużą liczbę atrybutów....
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Streszczenie: Dua liczba zwracanych (na przykład przez rónego rodzaju wyszukiwarki internetowe) dokumentów oznacza, e często zmuszeni jesteśmy do czasochłonnego ich przeglądania, celem weryfikacji trafności zwracanych wyników. Gdy dokumenty są długie, czas ich przeglądania znacznie się wydłua. Mona by go wydatnie skrócić, gdyby istniała moliwość au...
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Abstrakt. Powszechny dostęp do wydajnych i względnie tanich systemów baz danych powoduje, iż ilość przechowywanych danych jest ogromna i ciągle rośnie. Często skutkuje to tym, że gromadzone w dużych ilościach dane są praktycznie bezużyteczne w swojej surowej, nieobrobionej postaci. Różne techniki eksploracji danych starają się uczynić te dane bardz...
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Abstrakt. W pracy omówiono najnowsze wersje narzędzi firmy Oracle wspierających tworzenie aplikacji raportujących. Przedstawiono moduł Reports z pakietu Oracle Developer Suite oraz, w kontekście porównania z nim, nowe rozwiązanie firmy Oracle XML Publisher. W części poświęconej pierwszemu rozwiązaniu sku-piono się m.in. na tych elementach, które są...
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Streszczenie: Praca dotyczy problematyki estymacji nie-parametrycznej funkcji gęstości prawdopodobieństwa. Korzystając z bardzo bogatej bazy danych z wynikami różnych sondaży społecznych przeprowadzonych w Polsce w latach 1992-2008 wyznaczono stosowne krzywe gęstości prawdopodobieństwa. Otrzymane krzywe wykorzystano następnie, jako bardzo łatwe i w...
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Streszczenie: W artykule omówiono zakończony sukcesem projekt budowy zaawanso-wanej wyszukiwarki danych zgromadzonych w istniejącym na Uniwersytecie Zielonogór-skim Systemie Komputerowej Ewidencji Publikacji SKEP (adres internetowy: publika-cje.uz.zgora.pl). Wyszukiwarka powstała w oparciu o moduł Oracle Text, który jest częścią serwera bazodanoweg...
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Abstrakt. W artykule pokazano wybrane metody redukcji wymiarowości zbioru danych numerycznych. Celem redukcji jest albo odkrywanie niewidocznych związków zachodzących w tych danych, albo też użyteczna ich wizualizacja (lub jedno i drugie). Posłużono się kilkoma wybranymi metodami, w większości natury statystycznej, oraz metodą opartą na działaniu s...

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Project (1)
Project
FFT-Based Fast Bandwidth Selector for Multivariate Kernel Density Estimation FFT-Based Fast Computation of Multivariate Kernel Density Estimators with Unconstrained Bandwidth Matrices FPGA-Based Bandwidth Selection for Kernel Density Estimation Using High Level Synthesis Approach