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Medical ultrasound (US) systems are widely used for the diagnosis of internal tissues. However, there are challenges associated with acquiring and interpreting US images, such as incorrect US probe placement and limited available spatial information. In this study, we expand the capabilities of medical US imaging using a robotic framework with a high level of autonomy. A 3D camera is used to capture the surface of an anthropomorphic phantom as a point cloud, which is then used for path planning and navigation of the US probe. Robotic positioning of the probe is realised using an impedance controller, which maintains stable contact with the surface during US scanning and compensates for uneven and moving surfaces. Robotic US positioning accuracy is measured to be 1.19± 0.76mm. The mean force along US probe ${z}$ –direction is measured to be 6.11±1.18N on static surfaces and 6.63±2.18N on moving surfaces. Overall lowest measured force of 1.58N demonstrates constant probe-to-surface contact during scanning. Acquired US images are used for the 3D reconstruction and multi-modal visualization of the surface and the inner anatomical structures of the phantom. Finally, K-means clustering is used to segment different tissues. Best segmentation accuracy of the jugular vein according to Jaccard similarity coefficient is measured to be 0.89. With such an accuracy, this system could substantially improve autonomous US acquisition and enhance the diagnostic confidence of clinicians.

Waveforms distortion is a pressing concern in Smart Grids where a massive presence of new technologies in distributed energy resources and in advanced smart metering systems is expected. In this context, the increasing diffusion of high switching frequencies static converters and the growing usage of Power Line Communication push for research dealing with the assessment of waveforms with spectral components up to 150 kHz. The analysis of such waveforms is a challenge for researchers due to the contemporaneous presence of a high number of spectral components in the range of low- (up to 2 kHz) and high- (up to 150 kHz) frequencies, with their opposite needs in term of time window length (and frequency resolution). The main idea of this paper is to improve the performances of existing methods by using a joint method of analysis based on a profitable strategy of divide and conquer; the method guarantees the best compromise between accuracy and computational efforts. A Discrete Wavelet Transform initially divides the original waveform to obtain two frequency bands: the wavelet suitability for conducting multi-resolution time-frequency analysis on waveforms in different frequency bands with different frequency resolution is effectively exploited. Then, the sliding-window modified ESPRIT method and the sliding-window Discrete Fourier Transform which uses a Nuttal window are used for the analysis of the low- and high-frequency bands, respectively; the positive characteristics of each method are exploited, minimizing the drawbacks and integrating their behavior so that the whole joint method allows an accurate estimation of each low- and high-frequency spectral component with the required acceptable computational efforts. The proposed method is tested on synthetic and measured waveforms in terms of accuracy and computational efforts. The analysis of the numerical application results clearly reveals that the proposed method improves the performances of existing methods of analysis in the examined cases.

The paper discussess the power quality (PQ) assessment in point of common coupling (PCC) of a photovoltaic power plant (PVPP). The analyzed PVPP is a 3-phase 15 kW system localized at Wroclaw University of Science and Technology in Poland. Each phase of the system is different panel technology, as follows monocrystalline (MONO), thin layer copper indium gallium selenide (CIGS), polycrystalline (POLY). The analyzed period of time is 1 year – whole 2018 year. The measurement data was obtained from the stationary power quality monitoring system. In extension, to classic PQ assessment, the statistical analysis was presented.

In this study we developed an algorithm for spontaneous green space identification in the cities. The algorithm was developed based on NDVI analyses (calculated from Sentinel-2 data) in Warsaw's green spaces, Poland. We analysed NDVI values in nearly 2000 points which allowed us to develop an algorithm for a distinction between managed and spontaneous vegetation, the algorithm results show that in all vegetation classes NDVI values obtained for managed vegetation are lower than for spontaneously occurring one. Application of algorithm requires a time series of satellite images, for all each of them, the NDVI threshold value is calculated. Finally, based on the number of exceedances of the threshold value each green space pixel is assigned to managed or spontaneous vegetation class. The validation shows that the algorithm achieves 70% accuracy for both classes.

One of the VPP aspects are technical requirements concerning power quality (PQ). This work presents an idea and implementation of global power quality index (GPQI) for the assessment of multipoint power quality measurements collected in the area of the VPP. Proposed in this article GPQI has a synthetic character and is based on selected classical 10-min aggregated PQ parameters and additionally extended by extremum 200ms values of voltage changes and total harmonic distortion in voltage. The assessment using proposed GPQI is performed on the basis of real measurements in medium voltage distribution network in the VPP area including: main substation, hydro power plant (HPP), energy storage system (ESS). It was shown that using a proposed index it is possible to indicate mutual relations between substation and HPP and ESS.

One of the components of the VPP virtual power plant is electrical energy storage. Depending on the chosen technology, the storage has specific advantages and disadvantages, risks and limitations. The most frequently chosen technology is battery energy storage based on lithiumion batteries. The article presents the structure and principle of operation of lithium-ion batteries and presents a summary of the existing risks and limitations based on the literature. A sample test of energy storage with different capacities and charging characteristics is shown.

This article presents big data analysis, based on the measurements from a stationary power quality (PQ) monitoring system of a 15 kW PV power plant. The study period is one year – 2018. In the article, a unified PQ database was proposed, which consists of PQ parameters and active power level. Then cluster analysis (CA) was performed to indicate the different working conditions of a PV power plant. The Ward algorithm was selected to obtain the automatic classification due to the data features. The importance rate of parameters for each classification was calculated, to indicate which parameters were important in point of different clusters obtained. Additionally, the PQ level comparison between the clusters was realized to assess the indicated working conditions of a PV power plant.

The paper presents a simulation of the energy storage power control following predefined charge characteristics. The demand of local power consumers exceeding the given margin should be covered by the local generation (hydroelectric power plant) and from an energy storage system. The energy storage unit can be charged by the energy generated by the power plant and the energy from the power system. A storage control scenario was developed, where the main goal is to limit to the set level of power exchanged with the power system. Simulation calculations were carried out using data recorded in a real power system. The paper shows the influence of selection of energy storage unit characteristics and different generation cases on the operation of the whole system.

The voltage dip is one of the prominent disturbances in power systems related to power quality. Therefore it is very important to investigate the methods which allow to determine voltage dip direction finder. In this work selected voltage dip source location methods are discussed and investigated. The analysis are performed in Matlab Simulink environment. The methods are tested using different kind of fault and different fault location. The dip direction is indicated using two selected methods based on analysis of energy and impedance variation during the disturbance. The methods are applied for the measurements aggregated in different nodes of power systems, representing supply and customer side respectively. Based on the results of the dip direction achieved by investigated methods a general conclusions are formulated about the correctness, advantages and disadvantages of the discussed methods.

This paper presents simulation results of infinite control set model predictive control implemented into three-phase AC/DC converter. The connection between the converter and electric grid is made through LCL filter which is characterized by a better reduction of grid current distortions and smaller (cheaper) components in comparison to L-type filter. On the other hand, this type of filter can cause strong resonance at specific current harmonic which are efficiently suppressed by the control strategy which focuses on the strict control of the voltage vector of input filter capacitors. The presented method links benefits of using linear control methods based on space vector modulator and the non-linear ones which allow obtaining good control performance in steady state as well as in a transient state.

The use of magnetically-actuated catheters has the potential to facilitate minimally-invasive surgical procedures. In this work we present a magnetically-actuated tentacle catheter for object manipulation in remote areas of human body. The catheter employs a bio-inspired technique of under-actuated grasping. The whole body of the catheter loops around the target object, providing form closure necessary for manipulation. The catheter employs a permanent magnet to steer the position of its tip, and an electromagnetic coil to strengthen the maximum force applicable to the target object. We test the catheter in a series of proof-of-concept experiments. In a thermal study, we show that within the operational conditions, the heat dissipated by the coil allows for safe operation of tentacle catheter within human body. Subsequently, we characterise the maximum force available for manipulation using force sensor. The tentacle catheter can apply forces up to 0.1 N, which is in accordance with finite-element simulation. This force is sufficient for object manipulation in surgical tasks, such as biopsy. Finally, we demonstrate the operation of the tentacle catheter in a task involving manipulation of porcine tissue.

This paper presents an extended definitions of global power quality indices (GPQIs) applied for analysis of multipoint power quality measurements. A definitions of two GPQIs has been performed introducing aggregated data index (ADI) and flagged data index (FDI). The ADI is based on selected classical PQ parameters like frequency, RMS level, flicker severity, unbalance, harmonics. The aggregation time of particular PQ parameters is typical 10 minutes and the flagged data are extracted. Additionally definition of ADI is extended including parameters of envelope of voltage deviation created by maximum and minimum of 200 ms rms values within 10 minutes. As the support for ADI the FDI definition use extracted number 10 minutes flagged date which are rejected from classical power quality assessment due to abnormal state of the system work. Introduced definitions of ADI and FDI has been tested on the basis of real multipoint power quality measurements performed in mining industry power system. Using definition of proposed GPQIs allowed to assess impact of distributed generation (DG) on local working condition of electrical power network.

This paper presents a single-ended method for fault location (FL) in HVDC transmission line, when one terminal measurement data is used without using communication channel or synchronization links between two terminals. The technique is based on extracting traveling wave (TW) impulses from measured transients and its comparison with so called finger print (FP) i.e. referenced time schemes of TW impulses obtained by a use of banks of many Bewley's lattice diagrams of TW impulses related to different fault location. The method can be applied for homogenous line as well as for mixed cable-overhead line. The method was validated using PSCAD models of overhead line and segmented line. Presented results shows that the method is valid and capable for locating the faults and introduce new solution for single-ended technique in homogenous or segmented HVDC transmission lines.

This paper presents the results of using data mining for analysis of long-term power quality (PQ) data recorded in a supply power network of the mining industry. The analyzed network is characterized by prominent load variation caused by welding machines, conveyor belts and drainage pumps. Additionally, a distributed generation (DG, DER) is installed in the network represented by combined heat and power plant (CHP) and steam-gas generation units. In order to explore the PQ data, a cluster analysis (CA) is proposed a prominent representative of data mining (DM). Obtained results allow to indicate CA as a proper method for automatic identification of voltage event that is valuable for flagging concept as well as identification of periods of time when the network reveals different working conditions. It allows finally to investigate and compare the influence of distributed generation on electric power network of the mining industry.

This paper presents an outline of novel approaches and emerging trends related to Human-Computer Interaction (HCI). These trends have been present in the MIDI 2017 conference organized within FedCSIS series. In particular on-line services and mobile applications, often operated by voice-based interfaces and voice-driven assistants, are special areas of interest as to their prospective developments. Also the use of Artificial Intelligence (AI) in user interfaces seems to offer a breakthrough towards more intuitive and error-tolerant interaction needed especially in the most common, mobile context of use.

Magnetic interaction can be utilized for remote actuation of surgical manipulators. However, platforms currently available for that purpose have limited workspaces, inadequate field strength or very low bandwidth of the electrical subsystem. In this paper, we present BigMag, a novel platform capable of magnetic steering of continuum manipulators for medical purposes. BigMag comprises of 6 mobile coils and is capable of generating the fields of at least 40 mT in any direction at every point of its workspace. Moreover, we introduce a mathematical model for 3D mobile coil arrays. Each coil is modelled using finite element data adjusted by measurement-based correction, (a maximum observed mean error between the model and the prediction of 3.36 ± 5.62%). The model for a full system is validated in two tasks. In the first task, the system executes a prescribed rotating field (mean error between the model and measurement of 7.51% and minimum R2 of 0.964). The second task tests the estimation of the field for known 3D trajectories (minimum R2 of 0.967). The investigation concludes with a demonstration of BigMag capabilities in actuation of magnetic catheters in confined spaces usinguser-controlled steering.

Due to a controversial enrollment policy in most engineering programs at German Universities of Applied Sciences (UAS), many freshmen show very low school grades in key subjects like Math and Physics. Nevertheless they expect to be entertained in the lectures and get demotivated easily. Despite initial reservations, a cheer-and-challenge approach was developed for teaching Mechanics to freshmen having very diverse school grades. When tested, it showed astonishing results.

Matrices transformation of voltage and current transformers represent the amplitude and angular relationships between the voltages and currents of the secondary side and primary side. As a result, the selected state of asymmetry can be otherwise characterized by the primary and secondary side of the transformer depending on the connection system. For example, single-phase asymmetry on the primary side of the transformer Yd5 can be recognized as two-phase asymmetry on the secondary side. This paper presents the results of applying of voltage and current transformation introduced by transformers as a part of the algorithm for voltage dip propagation assessment.

Current methods for measurement and analysis of power quality is based on the selection of a representative period of time, usually a week, corresponding to normal operating conditions. However such conditions as variability of load and generation or changing the configuration of power system network may have a significant impact on the quality parameters of power system. In order to distinguish and perform comparative assessment of different states of the power system condition in terms of power quality parameters it is possible to use cluster analysis. This paper presents the results of the use of cluster analysis of long-term power data quality electricity recorded synchronously in selected fields of distribution substation 110/20/10kV.

The aim of this work is to analyze possibility of using parameters of an oscillating transient component which appears during fault condition in HVDC systems for detection and localization of faults. Two main parameters of mentioned components are considered, amplitude and frequency, which naturally are associated with parameters of circuits during fault determined by location of the fault. Proposed principle of the method is based on a reference characteristic between parameters of the oscillating component and the fault location. This reference function can be created using benchmarking transient signals. Using this function fault location can be estimated using amplitude and frequency of transient oscillating component. The parameters of the oscillating transient component a Prony method is proposed. Advantage of the method is possibility for application in the measurement systems with low sampling rate in the range of 5–100kHz. This condition locate proposed method as alternative or supplemented to traveling wave method which requires high sampling rate systems due to high time resolution requirements.

This paper presents principles of consideration of transformer winding connections in process of transfer of voltage dips across transformer. The aim of the work is to define transformation matrices and investigate its application for different types of voltage dips. Results of the algorithm with implemented transformation matrices is presented. The transformation matrices can be used for correction of the decision about dips direction finder.

Thearticle presents Finite Control Set Model Predictive Control for an AC/DC converter with a LCL filter. The extended cost function J is responsible for the adjustment of controlled values. An important issue raised in the article is the impact of dead time on the prediction of controlled values. The negative impact of dead time results in an increased THD of the grid current. The article proposes an algorithm correcting the impact of dead time which was confirmed by the results of Matlab-Simulink simulations and laboratory tests.