Przemyslaw Sypka

Lossless Jpeg-Base Compression of Transmultiplexed Images

A transmultiplexer assigned to combine images into one image to be sent through a single communication channel is presented. The considered system can be equipped with integer-to-integer filters to enable the lossless compression. The efficiency of lossless JPEG compression applied to transmultiplexed signals has been verified

Methodology to estimate variations in solar radiation reaching densely forested slopes in mountainous terrain

Solar radiation reaching densely forested slopes is one of the main factors influencing the water balance between the atmosphere, tree stands and the soil. It also has a major impact on site productivity, spatial arrangement of vegetation structure as well as forest succession. This paper presents a methodology to estimate variations in solar radiation reaching tree stands in a small mountain valley. Measurements taken in three inter-forest meadows unambiguously showed the relationship between the amount of solar insolation and the shading effect caused mainly by the contour of surrounding tree stands. Therefore, appropriate knowledge of elevation, aspect and tilt angles of the analysed planes had to be taken into consideration during modelling. At critical times, especially in winter, the diffuse and reflected components of solar radiation only reached some of the sites studied as the beam component of solar radiation was totally blocked by the densely forested mountain slopes in the neighbourhood. The cross-section contours and elevation angles of all obstructions are estimated from a digital surface model including both digital elevation model and the height of tree stands. All the parameters in a simplified, empirical model of the solar insolation reaching a given horizontal surface within the research valley are dependent on the sky view factor (SVF). The presented simplified, empirical model and its parameterisation scheme should be easily adaptable to different complex terrains or mountain valleys characterised by diverse geometry or spatial orientation. The model was developed and validated (R2 = 0.92 , σ = 0.54) based on measurements taken at research sites located in the Silesian Beskid Mountain Range. A thorough understanding of the factors determining the amount of solar radiation reaching woodlands ought to considerably expand the knowledge of the water exchange balance within forest complexes as well as the estimation of site productivity.

Robustness of transmultiplexed images

Transmultiplexation changes the parallel transmission into a serial transmission. The paper presents the suitable data preprocessing method of error reduction for images transmitted by transmultiplexer system. The solution is based on blocks of sizes adequate to separation filter orders, used in detransmultiplexation. The proposed method results directly from the detransmultiplexation algorithm. An example of a four-channel transmultiplexer system is presented and analyzed to illustrate the suggested method

Lossy Compression Approach to Transmultiplexed Images

The application of image compression methods in transmultiplexer systems is presented. The specific energy distribution in the combined image spectrum makes the standard compression methods, especially these that base on frequency decomposition not efficient. Two cases are described and compared: the compression of combined image and the preliminary compression of input images before transmultiplexing. Wavelet packet decomposition was used to obtain the frequency decomposition of images. Multirate processing involves digital filters that may be used to process images continuously. The results of conducted experiments are presented. The luminance of the transmitted image is calculated using formulae, which include both, upsampling and digital filtering. The combined image can be sent over a single transmission channel

Assessment of thermal diffusion in the natural biological environment

Abstract In this article, the application of the Ångström method in estimating the thermal diffusion parameter in an example of natural biological environment is described. The present study is based on measurements performed in forest soils. The main advantage of the suggested procedure is that it does not need the collection of samples of the soil for a later study in the laboratory. Collecting such data is typically very laborious and requires the preservation of the natural content and structure of all elements of the soil profile in the samples, such as organic components, soil parts, or rocks. The harmonic time runs necessary to implement the Ångström method were computed with the short-time Fourier transform. The obtained results, compared with reference values taken from literature, confirm the accuracy of the proposed methodology.

Should the Lopot-Plot Be Used in Daily Practice to Optimise Hemodialysis Treatment?

ABSTRACT The paper presents an application of the Lopot-plot, which compares the timeaveraged concentration (TAC) and the time-averaged deviation (TAD) of the weekly dialysis cycle, to comprise the results of intensive computational study. The presented case is based on 420 one-week-cycle simulations to verify the consequences implied by the change of the treatments schedule from nonuniformly to uniformly distributed over the week. The concept of steady state is explained and utilized to obtain periodical runs of the urea concentration. The presented graphs encouragingly indicate the potential of such plots in presenting results of multivariable intensive computations that should be advisably performed during the planning process of hemodialysis treatment.

Software Simulator to Design and Verify Transmultiplexer Systems

A transmultiplexer combines several signals into one signal to be sent through a single communication channel. At the receiver end the combined signal is split to recover the transmitted signals. The crosstalk between output signals must be zero. A simulator, which enables to design and verify the properties of transmultiplexer systems, is presented. Due to the applied integer-value filters, the perfect reconstruction condition is strictly realized in practical applications. An example of the 4-channel polyphase transmultiplexer is also presented.

Robustness of 1-D integer-to-integer transmultiplexer systems

An attempt to upgrade the robustness of telecommunication systems in which some packets can be lost is presented. The specific properties of the combined signal in transmultiplexer systems make it be possible to provide almost undetectable small errors to many end-users, instead of a serious error to one end-user only. Some experimental data obtained for the 4-channel integer-to-integer transmultiplexer are presented.

Robustness Of Transmultiplexed Images

Transmultiplexation changes the parallel transmission into a serial transmission. The paper presents the suitable data preprocessing method of error reduction for images transmitted by transmultiplexer system. The solution is based on blocks of sizes adequate to separation filter orders, used in detransmultiplexation. The proposed method results directly from the detransmultiplexation algorithm. An example of a four-channel transmultiplexer system is presented and analyzed to illustrate the suggested method

Application of 1-D Transmultiplexer to Images Transmission

The system that combines several images into a single signal appropriated for transmission by a 1-D communication channel is presented. A transmultiplexer equipped with integer-to-integer filters is applied to image transmission. Due to the incorporating of integer filters, a perfect reconstruction can be realized not only theoretically but also in practice. Such systems process signals using only the operations of multiplication and addition or subtractions of integer numbers. The new method of transmultiplexer filter design is presented. This method allows calculating separation filters arbitrary assuming composing ones. The computational algorithm, which results from a delivered theorem, and a simple example, is presented