The designing of transmultiplexer systems relies on determining filters for the transmitter and receiver sides of multicarrier communication system. The perfect reconstruction conditions lead to the bilinear equations for FIR filter coefficients. Generally there is no way of finding all possible solutions. This paper describes methods of finding a large family of solutions. Particular attention is devoted to obtaining algorithms useful in fixed-point arithmetic needed to design the integer filters. As a result, the systems perform perfect reconstruction of signals. Additionally, a simple method is presented to transform any transmultiplexer into an unlimited number of different transmultiplexers. Finally, two examples of integer filters that meet perfect reconstruction conditions are shown. The first illustrates a FIR filter which does not require multiplications. The frequency properties of filters and signals are discussed for the second example.

This article presents an efficient method of modelling acoustic phenomena for real-time applications such as computer games. Simplified models of reflections, transmission, and medium attenuation are described along with assessments conducted by a professional sound designer. The article introduces representation of sound phenomena using digital filters for further digital audio processing.

In this article the authors investigated and presented the experiments on the sentence boundaries annotation from Polish speech using acoustic cues as a source of information. The main result of the investigation is an algorithm for detection of the syntactic boundaries appearing in the places of punctuation marks. In the first stage, the algorithm detects pauses and divides a speech signal into segments. In the second stage, it verifies the configuration of acoustic features and puts hypotheses of the positions of punctuation marks. Classification is performed with parameters describing phone duration and energy, speaking rate, fundamental frequency contours and frequency bands. The best results were achieved for Naive Bayes classifier. The efficiency of the algorithm is 52% precision and 98% recall. Another significant outcome of the research is statistical models of acoustic cues correlated with punctuation in spoken Polish.

A phoneme segmentation method based on the analysis of discrete wavelet transform spectra is described. The localization of phoneme boundaries is particularly useful in speech recognition. It enables one to use more accurate acoustic models since the length of phonemes provide more information for parametrization. Our method relies on the values of power envelopes and their first derivatives for six frequency subbands. Specific scenarios that are typical for phoneme boundaries are searched for. Discrete times with such events are noted and graded using a distribution-like event function, which represent the change of the energy distribution in the frequency domain. The exact definition of this method is described in the paper. The final decision on localization of boundaries is taken by analysis of the event function. Boundaries are, therefore, extracted using information from all subbands. The method was developed on a small set of Polish hand segmented words and tested on another large corpus containing 16 425 utterances. A recall and precision measure specifically designed to measure the quality of speech segmentation was adapted by using fuzzy sets. From this, results with F-score equal to 72.49% were obtained.

Reverberation is a common problem for many speech technologies, such as automatic speech recognition (ASR) systems. This paper investigates the novel combination of precedence, binaural and statistical independence cues for enhancing reverberant speech, prior to ASR, under these adverse acoustical conditions when two microphone signals are available. Results of the enhancement are evaluated in terms of relevant signal measures and accuracy for both English and Polish ASR tasks. These show inconsistencies between the signal and recognition measures, although in recognition the proposed method consistently outperforms all other combinations and the spectral-subtraction baseline.

The goal of this article is to present and compare recent approaches which use speech and voice analysis as biomarkers for screening tests and monitoring of some diseases. The article takes into account metabolic, respiratory, cardiovascular, endocrine, and nervous system disorders. A selection of articles was performed to identify studies that assess voice features quantitatively in selected disorders by acoustic and linguistic voice analysis. Information was extracted from each paper in order to compare various aspects of datasets, speech parameters, methods of applied analysis and obtained results. 110 research papers were reviewed and 47 databases were summarized. Speech analysis is a promising method for early diagnosis of certain disorders. Advanced computer voice analysis with machine learning algorithms combined with the widespread availability of smartphones allows diagnostic analysis to be conducted during the patient’s visit to the doctor or at the patient’s home during a telephone conversation. Speech analysis is a simple, low-cost, non-invasive and easy-toprovide method of medical diagnosis. These are remarkable advantages, but there are also disadvantages. The effectiveness of disease diagnoses varies from 65% up to 99%. For that reason it should be treated as a medical screening test and should be an indication of the need for classic medical tests.

The technology of producing castings of high-quality inoculated cast iron with flake graphite particles in the structure is a combination of the melting and inoculation process. Maintaining the stability of the strength and microstructure parameters of this cast iron is the goal of a series of studies on the control of graphitization and austenitic inoculation (increasing the number of primary austenite dendrites), and which affects the type of metal matrix in the structure. The ability to graphitize the molten alloy decreases with its holding in the melting furnace more than an hour. The tendency to crystallize large dendritic austenite grains and segregation of elements such as Si, Ni and Cu reduce the ductility properties of this cast iron. The austenite inoculation process may introduce a larger number of primary austenite grains into the structure, affecting the even distribution of graphite and metal matrix precipitation in the structure. Known inoculation effects the interaction (in low mass) of additives: Sr, Ca, Ba, Ce, La, produces MC2 carbide). Addition of Fe in the inoculant influences the number and shape of austenite dendrites. Hybrid modification combines the effects of these two factors. The introduction of nucleation sites for the graphite eutectics and primary austenite grains result in the stabilization of the cast iron microstructure and an increase in mechanical properties. The obtained test results set the direction for further research in this area in relation to the production of heavy plate castings in vertical and horizontal pouring.

The article presents selected issues related to the development and testing of the diagnostics systems dedicated for superconducting electromagnets. The systems were constructed to assess the production quality of superconducting electromagnets of the SIS100 synchrotron, a new accelerator being built as part of the Facility of Antiproton and Ion Research (FAIR). One of the systems is used for automatic checking of electrical connection parameters and the continuity of electric circuits. The role of the second device is to assess the quality of winding insulation and to estimate circuit parameters of electromagnet coils using the capacitor discharge method. The work presents measurements and analysis of current and voltage waveforms acquired during discharges on a magnet coil simulator and on the SIS100 main dipole electromagnet.

This article is a description of the progress of research and development in the area of massive large-scale castings - slag ladles implemented in cooperation with the Faculty of Foundry Engineering of UST in Krakow. Slag ladles are the one of the major castings that has been developed by the Krakodlew (massive castings foundry) for many years. Quality requirements are constantly increasing in relation to the slag ladles. Slag ladles are an integral tool in the logistics of enterprises in the metallurgical industry in the process of well-organized slag management and other by-products and input materials. The need to increase the volume of slag ladles is still growing. Metallurgical production is expected to be achieved in Poland by 2022 at the level of 9.4 million Mg/year for the baseline scenario - 2016 - 9 million Mg/year. This article describes the research work carried out to date in the field of technology for the production of massive slag ladles of ductile cast iron and cast steel.