Wyniki 1-4 spośród 4 dla zapytania: authorDesc:"TOMASZ P. ZIELIŃSKI"

OFDM VS wavelet-ofdm and circular wavelet-ofdm in high speed communication over power lines

  Orthogonal Frequency Division Multiplexing (OFDM) was adapted to many future communication systems due to its simple and elegant implementation resulting from usage of cyclic prefi x, IFFT/FFT based modulator and demodulator [1]. However, OFDM is commonly believed to have a poor spectral characteristic because of relatively high side lobes of adjacent carriers. This is the main reason of proposing the alternative multicarrier modulation schemes for communications purposes. One of the well known is Discrete Wavelet MultiTone (DWMT), also recently proposed for high-speed communications over power lines under the name of Wavelet- OFDM [2]. The mentioned here main OFDM’s drawbacks can be overcome by using specially designed fi lters. Unfortunately, the Wavelet-OFDM system do[...]

Level set based automatic segmentation of ultrasound echocardiographic images

  Cardiovascular system diseases are responsible for over 7 million premature demises in the world per year. One of the main factor of cardiovascular risk is hypertension leading, among others, to left ventricle rebuilding. Therefore measurement of left ventricle shape in ultrasound B mode examination is recognized as one of the main medical noninvasive examination aiming at estimation of the heart state and cardiovascular risk. Problem of effi cient segmentation and tracking left ventricle in ultrasound images is widely reported in literature [1-13]. In this paper novel usage of the level set method [14] to the heart segmentation is presented, the fi rst step leading towards segmentation of the left ventricle. Typically, in this case application of the active contours/shape segm[...]

Automatic estimation of the intima-media thickness of the common carotid artery

  Data published by World Health Organization (WHO) indicate that cardiovascular system diseases are responsible for over 7 milion premature demises in the world per year. One of the main factor of cardiovascular risk is hypertension leading to arterial vessels rebuilding. It was found in clinical research that hypertension causes thickening and remodelling of intima-media complex (IMC). Therefore measurement of intima-media thickness (IMT) of the common carotid artery in ultrasound B mode examination (see Fig. 1) is recognized as an effective noninvasive method of state valuation of arterial vessels and cardiovascular risk [1]. Due to subtlety of IMC rebuilding process and presence of strong disturbances in ultrasound images (speckles, refl ections, gaussian noise of electronic[...]

HFCC based recognition of bird species

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An acoustical analysis of bird voices is important and dynamically increasing aspect of the ornithological research. Identification of bird species can serve as an example. It is often used for educational and pedagogical purpose [3] but can also be applicable for biological and agricultural research and studies [4]. Specific application of the identification of bird species is detection of [...]

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