Portable Wearable Devices Research Articles

Flexible Fiber Shaped Self-Powered System Based on Conductive PANI for Signal Sensing and Energy Harvesting.

As science and technology advance, people are increasingly inclined to use sustainable and portable wearable electronic devices. The traditional supporting power source, batteries, suffers from issues of flexibility and lifespan, severely constraining the development of wearable devices. Alternatively, the self-powered system, serving as a power source, can effectively collect energy from the surrounding environment, achieving maintenance-free operation and high adaptability, which has attracted widespread research. The coaxial fiber-structured self-powering system proposed in this study is based on a supercapacitor (SC) and a triboelectric nanogenerator (TENG). The carbon fiber (CF) has polyaniline (PANI) and rGO connected to it, and a friction layer of silicone rubber is wrapped around the outside. The conductivity of the fiber was increased by multiple PANI graftings, and a coaxial fiber-type TENG with a 2 mm diameter was created. Following weaving, the TENG displays a high power density of 576 mW m-2 and an open-circuit voltage of 160 V and a short-circuit current of 9 μA. In addition, the flexible fiber-shaped supercapacitor uses NiAl-LDHs@CF as the negative electrode and AC@CF as the positive electrode, showing a specific capacitance of up to 281.4 mF cm-2. Furthermore, the SC and TENG are assembled into a coaxial self-power supply system, which has excellent performance and shows extensive potential applications in the field of wearable device power supply.

Automatic cinematography for body movement involved virtual communication

AbstractThe emergence of novel AI technologies and increasingly portable wearable devices have introduced a wider range of more liberated avenues for communication and interaction between human and virtual environments. In this context, the expression of distinct emotions and movements by users may convey a variety of meanings. Consequently, an emerging challenge is how to automatically enhance the visual representation of such interactions. Here, a novel Generative Adversarial Network (GAN) based model, AACOGAN, is introduced to tackle this challenge effectively. AACOGAN model establishes a relationship between player interactions, object locations, and camera movements, subsequently generating camera shots that augment player immersion. Experimental results demonstrate that AACOGAN enhances the correlation between player interactions and camera trajectories by an average of 73%, and improves multi‐focus scene quality up to 32.9%. Consequently, AACOGAN is established as an efficient and economical solution for generating camera shots appropriate for a wide range of interactive motions. Exemplary video footage can be found at https://youtu.be/Syrwbnpzgx8.

Continuous non-invasive arterial blood pressure monitoring with photoplethysmography via SE-MSResUNet network

ObjectiveArterial blood pressure (ABP) waveforms include physiological parameters closely related to BP values, while only a few studies predict BP values through the monitoring ABP waveforms. Current ABP waveforms monitoring methods are limited by its high computing cost and information redundancy of multi-channel input signals. The aim of our work is to propose a new end-to-end method for monitoring the ABP waveforms using single-channel photoplethysmography (PPG) signals by constructing a lightweight Multi-Scale Residual U-Net fused with Squeeze-and-Excitation module (SE-MSResUNet) model. MethodsFirstly, the PPG and ABP signals are preprocessed with denoising, segmentation, and eliminating phase difference. Subsequently, the SE-MSResUNet model is constructed and trained using training data to achieve the mapping relationship between PPG and ABP signals. Then, the BP values are extracted from the monitored ABP waveforms. Finally, the performance of the SE-MSResUNet in ABP waveform monitoring and BP estimation is investigated. ResultsThe ABP waveforms monitored by our proposed SE-MSResUNet network with PPG signals only are highly consistent with the reference ABP waveforms. The MAE ± SD of estimated diastolic blood pressure (DBP), mean arterial pressure (MAP) and systolic blood pressure (SBP) compared with reference values are 2.16 ± 3.75, 2.29 ± 3.72, and 3.88 ± 6.17 mmHg, respectively. The proposed method meets the Association for the Advancement of Medical Instrumentation (AAMI) standard and reach A level of the British Hypertension Society (BHS) standard. ConclusionsOur proposed method outperforms current state-of-the-art methods for non-invasive blood pressure monitoring from PPG signals. The algorithm provides a potential possibility for continuous non-invasive blood pressure monitoring through portable wearable devices.

Nonlinear features of photoplethysmography signals for Non-invasive blood pressure estimation

ObjectiveContinuous monitoring of blood pressure (BP) plays an essential role in the prognosis and prevention of hypertension and related cardiovascular diseases. Moreover, the ever-increasing demand for portable continuous health monitoring systems coupled with promising capabilities of photoplethysmography (PPG) sensors for developing easy-to-use, portable wearable devices have motivated many researchers toward applying PPG signals for non-invasive health monitoring. Nonlinear nature of BP and proven capability of the Poincaré plot for analyzing dynamic behavior of nonlinear systems motivated us to use this powerful tool for BP estimation. This study aims to explore the dynamical behavior of PPG signals to assist feature extraction for machine-learning (ML) algorithms to estimate BP. We proposed a Poincaré-based feature extraction method for BP estimation with no need to extract precise local points on the PPG signal. MethodsFirst, a Poincaré plot of 10-s segments of the PPG signal was prepared. Then, three distinct time series were retrieved from Poincaré mapping of PPG signals; following this, numerous indices were extracted from the three time series. The F-Test feature selection method was applied to pick the most effective features. Finally, the picked features were fed into different ML algorithms for the estimation of BP. ResultsThe proposed method was validated using a subset of the Medical Information Mart for Intensive Care II (MIMIC-II) database containing ambulatory blood pressure (ABP) and PPG records. The performance evaluation was carried out in terms of mean absolute error (MAE), standard deviation (STD), and Pearson’s correlation coefficient. According to the results, application of the Gaussian process regression (GPR) led to the best performance for both systolic and diastolic BP (0.79 ± 3.08 and 1.38 ± 4.53 mmHg, respectively). Satisfying the criteria for Advancement of Medical Instrumentation (AAMI), it was rated as Grade A for systolic and diastolic BP measurements under terms of British Hypertension Society (BHS) standards, which confirms the efficiency of the Poincaré-based features for BP estimation. ConclusionThe results justify the usefulness of the proposed Poincaré-based features as a powerful tool in BP estimation scenarios.

Designed formation of lignin-derived hollow particle-based carbon nanofibers for high-performance supercapacitors

This work constructs a 1D hollow particle-based carbon nanofibers (HCNFs) derived from Zn-based metal-organic-frameworks (MOFs) particles embedded in biomass-based electrospinning nanofibers as high-performance supercapacitor (SC) electrodes. Abundant mesopores are introduced by the pyrolysis of MOFs, which generates uniformly distributed electrolyte storage pools for a fast electrolyte ions channel. Owing to its uniquely hierarchical pore structure, the derived HCNFs exhibit much enhanced supercapacitive performance. The prepared HCNF-1000 electrode has not only a high specific capacitance (229.6 F g−1 at a current density of 2 A g−1) but also good rate performance (176.8 F g−1 at 10 A g−1, 99.1 F g−1 at 30 A g−1). The two-electrode symmetrical system HCNF-SC has an energy density of 5.1 Wh kg−1 when the power density is 0.5 kW kg−1. HCNF-1000-based solid-state supercapacitor HCNF-FSC shows good electrochemical performance even in different folded states, displaying the potential application value for the development of portable wearable devices.

Rapid visualized assessment of tetracycline in actual fruit samples: The combination of perovskite and rare earth complexes

The abuse of tetracycline (TC) has resulted in serious environmental pollution and the preparation of highly sensitive fluorescent probes capable of rapidly detecting TC has become a hot research field. All-inorganic halide perovskites have attracted extensive because of their good fluorescent properties, while the instability in polar solvents hinders its development for practical applications. In the present study, a perovskite quantum dot that can emit green fluorescence was prepared, and a ratio nanocomposite fluorescent probe (CsPbBr3@Cs4PbBr6@NH2@Eu) for the rapid visual assessment of TC in ethanol was obtained through functional modification by rare earth complexes. The continuous addition of TC led to the distinct color transition from green to red, resulting in the visualized multicolor sensing for TC. The probe had a good linear relationship with detection limit of 12.1 nM. The sensing mechanism research indicated that the quenching of perovskite nanocrystals in the probe was caused by the PET effect, and the red fluorescence enhancement was caused by the “antenna effect” produced by the chelation of TC with Eu3+. In addition, a portable wearable device for the fast visual detection of TC was developed to realize the rapid and intelligent detection of TC in actual fruit samples.

Construction of Stretchable and Large Deformation Green Triboelectric Nanogenerator and Its Application in Technical Action Monitoring of Racket Sports

The rapid development of E-Skin has attracted researchers’ attention to portable wearable devices. However, it is a great challenge to achieve high-output performance and high-environmental protection simultaneously. Polyhydroxybutyrate (PHB) has excellent electron-withdrawing ability and biodegradability, but its stretching ability is poor, which limits its application in portable wearable devices. In this paper, the biocompatible poly(lactide-co-caprolactone) (PLCL) was innovatively selected to modify the properties of the PHB electrospun membranes, and PHB/PLCL composite membranes with different contents of PLCL were constructed. Then, the expanded polytetrafluoroethylene (ePTFE) membranes and PHB/PLCL electrospun membranes were used as the friction layers to construct a flexible triboelectric nanogenerator (TENG). With the increase of PLCL contents, the elastic recovery rate of the composite membranes increased to 68% of tension at 40% strain. The toughness of the composite membrane was increased by 546%, which exhibits ultratoughness and stretchable properties. Based on the ultratoughness and high elasticity electrospun membranes with 50% PLCL, a stretchable and large deformation sensing device was made. The PHB/PLCL-ePTFE TENG could distinguish pingpong and badminton accurately, as well as their various postures such as forehand, backhand, smash poses, etc., which provided a new idea for large deformation monitoring of TENGs.

A flower bud-shaped flexible UWB antenna for healthcare applications

Remote surveillance of the elderly and others with health difficulties is becoming increasingly important in these epidemic days. To address these issues, low-cost, lightweight, and portable wearable devices are in huge demand. This paper realizes the design and analysis of a flexible ultra-wideband (UWB) antenna for healthcare applications. The proposed hexagonal microstrip antenna encompasses two cuts on the top left and right side of the hexagon which looks like a flower bud. The antenna is fabricated using a flexible foam substrate with a dielectric constant of 1.07 and has a dimension of 38 times 30 times 1.7,{text{mm}}^{3}. With a unique patch shape and corner cut in the partial ground, the present design strives to optimize the antenna structure to accommodate UWB (3.1 to 10.6 GHz) operating spectrum from 2.6 to 11.3 GHz. The proposed antenna has achieved an FBW of 125.17% with a total gain of 5.24 dB. The antenna is also evaluated on the line of bending and SAR over a tissue of 1 g and 10 g. The antenna operated admirably, with an average SAR value below the safety limits of 1.6 W/kg and 2 W/kg for the tissues, respectively.

An Accurate Non-accelerometer-based PPG Motion Artifact Removal Technique using CycleGAN

A photoplethysmography (PPG) is an uncomplicated and inexpensive optical technique widely used in the healthcare domain to extract valuable health-related information, e.g., heart rate variability, blood pressure, and respiration rate. PPG signals can easily be collected continuously and remotely using portable wearable devices. However, these measuring devices are vulnerable to motion artifacts caused by daily life activities. The most common ways to eliminate motion artifacts use extra accelerometer sensors, which suffer from two limitations: (i) high power consumption, and (ii) the need to integrate an accelerometer sensor in a wearable device (which is not required in certain wearables). This paper proposes a low-power non-accelerometer-based PPG motion artifacts removal method outperforming the accuracy of the existing methods. We use Cycle Generative Adversarial Network to reconstruct clean PPG signals from noisy PPG signals. Our novel machine-learning-based technique achieves 9.5 times improvement in motion artifact removal compared to the state-of-the-art without using extra sensors such as an accelerometer, which leads to 45% improvement in energy efficiency.

Shape Dependence of Silver Nanowires on Synthesis Conditions and it’s Effect on the Optical and Electrical Properties

As the market share of optoelectronic devices grows yearly, the transparent conductive electrodes that guarantee device performance subsequently gain attention. In order to solve the cost issue of the most commonly commercialised transparent conductive electrodes (indium tin oxide) and the problem that they cannot be used in portable wearable devices, flexible carbon-based hybrid nanomaterials are considered as an alternative. But, it still suffers the complicated synthesis process. Thus, silver nanowire (AgNW) is regarded as the most promising material with advantages of the facile synthesis process, high conductivity and transparency. The synthesis conditions and AgNW morphology are believed to be vital for their optical and electrical properties. This research investigated the effect of synthesis conditions (capping agent molecular weight and compositions, reaction temperature and the stirring rate) and discussed the connection between the optical transmission and electrical resistance of coated films fabricated by AgNW with various morphology. Results show that heavier capping agents with more viscous solutions are more favourable for long wire growth, and mixed capping agent solutions can achieve higher aspect ratios. Both relatively low reaction temperature and no stirring could prevent silver particles nucleation and agglomeration, achieving longer nanowires. The AgNW-coated film by nanowires with longer lengths could have more advantages in the trade-off between conductivity and transparency for better performance. This article illustrates and explains the influence of factors in the synthesis process on its morphology and functionality, creating more possibilities for the development and application of flexible transparent conductive electrodes.

A potential flexible fuel cell with dual-functional hydrogel based on multi-component crosslinked hybrid polyvinyl alcohol

The flexible energy supplies are urgently needed considering with the rapid development of portable wearable electronic devices. The fuel cells possess the highest theoretical power density compared with batteries and super-capacitors. However, the flexible and bendable applications are hindered by the inconvenient fuel/electrolyte storage and existence of physical membrane. It is necessary to develop one kind of power sources with a straightforward system and integrated fuel/electrolyte supply-storage system. Herein, a new type of hydrogel based on polyvinyl alcohol-polyvinyl pyrrolidone-sulfosuccinic acid semi-interpenetrating network, is synthesized and applied by doping and blending various functional groups. The hydrogel possess the characteristics of high swelling ratio, superior ionic conductivity, good mechanical properties and integrated dual functions. The flexible fuel cell integrated with fuel storage/supply hydrogel is assembled without any external auxiliary system. It delivers a maximum power density of 2.83 mW cm−2 and operates normally under various flexible situations such as bending, twisting, fatigue bending and needling states. Both high flexibility and stability of the hydrogel-based micro fuel cells have been demonstrated upon the wearable and bendable applications. The work illustrates a pathway for designing power sources for flexible electronics with integrated fuel/electrolyte storage and matched mechanical properties.

Portable Wearable Devices: Advanced Monitors Are Now in the Palm of Your Hand!

Portable Wearable Devices: Advanced Monitors Are Now in the Palm of Your Hand!

Flexible corrugated triboelectric nanogenerators for efficient biomechanical energy harvesting and human motion monitoring

The growing demand for the sustainable energy supply of portable wearable electronic devices has recently attracted much attention. The emergence of an environmentally friendly, renewable, and sustainable energy-supplying triboelectric nanogenerator (TENG) provides new potential and promising solution. However, it requires excellent structural stability and superior properties in practical applications. In this paper, a novel flexible corrugated triboelectric nanogenerator (C-TENG) with incredible elasticity, excellent durability and output performance for efficient energy harvesting and self-powered sensing has been designed and developed. For enhancement of electric performance, a study has also been carried out for investigating different structural parameters for the optimized performance of C-TENGs. The as-made C-TENGs have shown excellent and stable electric performance, outstanding mechanical durability and washing capability. The highly self-resilient structure of C-TENG enables its open-circuit voltage, short-circuit current, and power density to reach 480 V, 137 μA and 486 μW/cm2, respectively. Furthermore, the functional applications of C-TENG as smart insoles and intelligent carpets have been demonstrated. An intelligent system has also been developed to detect human motion and monitor people's stream scale on the intelligent carpet. This study proposes a new perspective for the structural design of TENGs and advanced applications in intelligent sensing.

Portable Multi Channel EEG Signal Acquisition System

This study introduces a portable multi-channel EEG signal acquisition system. The system is mainly composed of EEG electrode connector, signal conditioning circuit, EEG acquisition part, main control MCU and power supply part. The low-power EEG acquisition front-end ADS1299 and STM32 are used to form the signal acquisition and data communication part. The collected EEG signal can be transmitted to the PC for real-time display. After relevant tests, the system has small volume, low power consumption, high signal-to-noise ratio, and meets the requirements of portable wearable medical devices.

A Succinct Review on Piezoelectric Characteristics of PVDF and its Copolymer PVDF-HFP

Researchers are making attempts to develop a lightweight, shock resistance, portable, wireless sensors, and flexible wearable electronic devices. Piezoelectric nanogenerators are those which are used to convert mechanical into electrical energy and vice versa, which in turn meets the requirement of low-powered electronic gadgets. PVDF (Poly vinylidene difluoride) is found to be one of the versatile polymeric materials with intriguing characteristics and many technological applications. In recent days, Polyvinylidene difluoride and its copolymers like P(VDF-trifluoroethylene) and P(VDF-tetrafluoroethylene) are being explored extensively in order to produce energy harvesting devices. The present study deals with recent trends in the processing techniques of piezoelectric materials PVDF-HFP with different nano fillers in order to enhance its efficiency. This article may inspire several researchers to fabricate polymer composites of PVDF-HFP with different additives, which finds applications in several fields like shoe pad nanogenerator, biomedical, smart scaffolds, spin valve devices, and hybrid generators.

Financial Risk Control and Audit of Supply Chain under the Information Technology Environment

With the continuous improvement of society’s recognition of supply chain finance and the development of domestic enterprises, the scale of Chinese supply chain financial service market has become larger and larger, and the status of supply chain financial services has gradually become clear. This emerging financing method can solve the problem of financing difficulties for small- and medium-sized enterprises. Many commercial banks are involved, but there are also many risks. As a representative of industrial integration, how commercial banks manage risks and improve the financial service supply chain is the focus of the article’s research. The article designs a set of risk management system based on machine learning and trains similar models to verify consumers by learning user behavior patterns. The system realizes the server-side authentication module and the intelligent terminal protection module and achieves the purpose of real-time protection of the intelligent terminal system. The system will adapt to mainstream Android and IOS on the market, including portable terminal devices and smart wearable devices. If it is found that the device has not been operated by the user, the user will be provided with corresponding feedback results, and a series of automatic protection operations such as device lock and system alarm will be provided. At the same time, we provide two modes of online detection and offline detection. The device only needs to have our cloud user model to authenticate users in an offline environment to ensure that systems in different environments can run. The article solves the imbalance between user data and negative samples and most unlabeled user data and designs a set of management learning methods to ensure user certainty. By cooperating with enterprises, we can learn and analyze this set of data in our system. The results show that the accuracy rates of effective operation and user static data are 93.77% and 95.57%, respectively.

Synchronous nanogenerator with intermittent sliding friction self-excitation for water wave energy harvesting

The triboelectric nanogenerator (TENG) is a promising technology for harvesting low-frequency ocean energy, while a low surface charge density sets back its industrialization. Normally, owing to insufficient friction the traditional contact-separation mode has difficulty achieving a high surface charge density as that of sliding friction mode, which also can hardly maintain long-term sustenance due to abrasion. Herein, we designed a synchronous contact-separation triboelectric nanogenerator (SC-TENG) with intermittent sliding friction self-excitation that can achieve the dual functions of long-term sustenance of a high surface charge density and low friction-induced loss. A movable pendulum structure rotates intermittently to replenish the charge for its own, thus sustaining a high surface charge density for continuous contact-separation working mode. Several comparative experiments are conducted, showing short-time sliding friction made it easier to improve the surface charge density and output performance than long-term contact-separation friction. The single TENG with short-term friction increases by seven-fold in the transferred charges, 3.2 times in output current, compared to the TENG without friction. The SC-TENG could generate a high voltage of 1284 V and maximum peak power of 8.3 mW at 1 Hz. With those capacities, the TENG can easily capture the water wave energy to power a commercial thermohygrometer and portable wearable device. SC-TENG proposes an innovative design and a new strategy for preparing the TENG with high output and low loss.

Pressure-Induced Self-Interlocked Structures for Expanded Graphite Composite Papers Achieving Prominent EMI Shielding Effectiveness and Outstanding Thermal Conductivities.

High-performance films via layer-by-layer assembly of two-dimensional (2D) materials would provide all possibilities for the development of modern integrated electronics. However, the stacked structure between nanosheets and large-scale fabrication still remain a great challenge. Herein, Fe3O4/expanded graphite (EG) papers are fabricated via in situ oxidation of ferrocene onto EG nanosheets, followed by a continuous roll-in process. Upon mechanical compaction, the self-interlocked structures driven by close overlapping and hooking of nanosheets in Fe3O4/EG (FG) composites remarkably facilitate the construction of phonon and electron transmission channels and improve mechanical strength. FG papers exhibit prominent shielding effectiveness (67.1 dB at ∼100 μm) with enhanced absorptivity (∼0.1, surpassing lots of conductive film materials), stemming from the synergistic effect of electrical and magnetic properties. Also, the electromagnetic interference (EMI) shielding performance shows prominent reliability after bending (2000 cycles) and ultrasonic treatment (30 min). The corresponding tensile strength reaches 35.8 MPa; meanwhile, the corresponding in-plane thermal conductivity coefficient is as high as 191.7 W/(m·K), which can rapidly and efficiently accelerate heat dissipation. In particular, FG papers also reveal rapid response, controllable, and highly stable Joule heating performance and present promising prospects in the fields of radiation-proof clothing, flexible heaters, portable wearable devices, and aerospace.

A Fully-Differential Biopotential Amplifier With a Reduced Number of Parts

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Objective:</i> Fully differential topologies are well-suited for biopotential amplifiers, mainly for single-supply battery-powered circuits such as portable wearable devices where a reduced number of parts is desired. A novel fully differential biopotential amplifier is proposed with the goal of providing electrode offset rejection, bandwidth limitation, and a temporal response compliant with biomedical standards with only a single commercial quad operational amplifier (OA) integrated circuit. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Methods:</i> A novel compensation strategy was used to provide a transfer function with only one zero at the origin, which makes it easy to comply with the transient response imposed by biomedical standards. A topology with no grounded components was leveraged to obtain a common-mode rejection ratio (CMRR) ideally infinite and independent of components mismatches. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Results:</i> Design equations are presented and, as an example, an electrocardiogram (ECG) amplifier was built and tested. It features a CMRR of 102 dB at 50 Hz, 53 dB gain that supports DC input voltages up to ±300 mV when powered from a 0 V to 5 V single-supply voltage, and a cutoff frequency of less than 0.05 Hz with a first order response. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Conclusion:</i> A fully-differential biopotential front-end was designed and validated through experimental tests, demonstrating proper operation with only 4 OAs. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Significance:</i> The amplifier is intended for board-level design solutions, it can be built with off-the-shelf components that can be selected according to specific needs, such as reduced power consumption, low noise, or proper operation from a low-voltage power source.

Development of non-invasive methods and technical means for diagnosing posture disorders and spinal deformities

The purpose of this paper is to review the existing non-radiation methods and systems for diagnosing postural dis- orders and spinal deformities. Materials and research methods. Search for scientific articles on the database platforms „Web of Science“, „Scopus“, PubMed, Cochrane Library, eLIBRARY, CYBERLENINKA and using the Google Scholar search engine for keywords and phrases: three-dimensional gait analysis, dynamic sagittal balance, spinal kinematics, deformity spine, global sagittal alignment, degenerative lumbar kyphoscoliosis, posture, movement. Results. When analysing information on methods and systems for non-radiological diagnostics of postural disorders and spinal deformities, attention was primarily paid to the possibility of using such information for examination in dynamics; repeatability of results, their accuracy and reliability; correlation of the results of indirect determination of the Cobb angle to its true value, measured from the radiograph. An overview of the diagnostic possibilities and technical features using the methods of: moiré topography, raster stereography, laser scanning, three-coordinate electrogoniometry, portable (wearable) devices, marker video capture of motion. A compara- tive analysis of the methods of non-radiation diagnostics of spinal deformities is presented, considering their advantages and disadvantages. Conclusion. The method of marker video capture of motion is the closest to X-ray in terms of the reliability of the results of the assessment of the musculoskeletal system with the possibility of conducting tests in dynamics to assess the mobility of the spine, in the selection and adjustment of technical means of rehabilitation. But video analysis is characterized by the complexity of the survey, data processing and analysis. For long-term monitoring, portable devices are more suitable, but in terms of the reliability of diagnostic results, they are inferior to systems based on the motion capture method.