Technical Measurements Research Articles

Method and Algorithm for Estimating the Maximum Total Error of an Automotive LiDAR

The article proposes a method and an appropriate algorithm for estimating the error of the measurements of the LiDAR as a technical measurement system to “include” this evaluation in the given accuracy. A generic model for the LiDAR’s measurements is described, a mathematical model of the measurements with the total values of random and systematic errors is given. Based on this method the algorithm for estimating the maximum total error (not exceeding the accuracy of the measurement) is formed. The algorithm complies both with the mathematical description presented in the article, and the methodology described in Russian standard GOST R 8.736-2011. On the basis of the calculated estimate of the weighted average error, it is possible to construct a technical device, that provides a three-fold reserve in terms of measurement accuracy.

Clinical Evaluation Criteria for Automatic Diagnosis of 12-lead Electrocardiograph

The automatic diagnosis function of the electrocardiograph (ECG) machine directly affects the clinical application of the device. However, there is currently no unified criteria for the evaluation of the automatic diagnosis function of the 12-lead ECG machine in clinic. We established a 12-lead ECG automatic diagnostic function clinical evaluation specification from the scope of the specification, the automatic diagnostic function judgment rules, general technical measurement requirements, test methods and conditions, and ECG data input. Emphasis is given to the judgment rules of the automatic diagnosis function, including the accuracy of ECG feature values, the interpretation and judgment of automatic diagnosis results. This specification aims to provide technical basis for the clinical evaluation for automatic diagnosis function of the 12-lead ECG.

Effect of energy renovation and occupants' activities on airborne particle concentrations in Swedish rental apartments

Exposure to airborne particles causes detrimental health effects, hence their assessment in indoor environments, where people spend most of the time, is important. The influence of energy renovation and occupants' activities on airborne particle concentrations was assessed in seven occupied Swedish residences. Ultrafine particle (UFP, <100 nm) number concentrations, PM2.5 (<2.5 μm) and black carbon (BC, <900 nm) mass concentrations were simultaneously measured inside and outside before, after renovation, and during follow-up.The average indoor UFP number concentrations increased from 6200 (±4070) cm-3 before renovation to 12,700 (±6040) cm-3 during the follow up, as the number of indoor activities doubled. Indoor UFP number concentrations depended mainly on frequency and type of occupants' activities in studied residences (e.g., cooking, candle burning). The average indoor PM2.5 concentration decreased from 8.6 (±5.8) μg m-3 before renovation to 2.5 (±1.3) μg m-3 during follow up, as the activities that generated PM2.5 decreased, and infiltration of outdoor particles could have been decreased due to renovation measures. However, the indication of infiltration decrease during the follow up, assessed on the basis of indoor to outdoor ratios during non-activity times (with no influence of occupants' activities), was not observed after the renovation and should be treated with caution. In this study indoor PM2.5 and BC were influenced by activities and outdoor concentrations. Reduction of exposure to indoor UFP, might be obtained by optimization of kitchen exhaust flows. An improved design of supply air inlets in mechanical exhaust ventilation systems may reduce PM2.5 infiltration.Occupants' logbook records, needed for identification of sources contributing to particle exposure, proved useful but not always accurate compared to technical measurements of activities and UFP concentrations. Development of simple and reliable activity detection systems is needed to complement logbooks and allow accurate assessment of source contribution to particle exposure in homes and associated health effects.

Sex and age biological variation of the mandible in a Portuguese population- a forensic and medico-legal approaches with three-dimensional analysis

The medico-legal identification is based on a set of discriminatory characteristics between individuals in their biological, social, cultural, religious, legal and economic framework.The purpose of this study was to characterize the biological variation, regarding gender and age, in a Portuguese population. A three-dimensional (3D) analysis of 215 mandibles (7–20 years old) from the database of the Laboratory of Forensic Dentistry, Faculty of Medicine, University of Coimbra (CE-112/2019) was performed.A total of 13 cephalometric points defined 10 linear variables and 7 angular variables, on 3D reconstructions from ConeBeam Computed Tomography (CBCT) images. Intra and inter-observer errors were analyzed by Technical Measurement Error test. A descriptive statistics was performed. To verify the influence of gender and age on the variables and to determine its predictive value, ANOVA and Logistic Regression Analysis were performed.Gender and age influence most of the linear variables, however, the same is not true for angular variables. In the analysis of all variables, the model has a reasonable level of sensitivity (67.8%) according to gender. For the age prediction, with all variables, the model presented a reasonable level of sensitivity, classifying 79.4% of the individuals.The results supported, with a high level of statistical significance, an adequate recognition of individuals highlighting the identification and criminal imputability of Portuguese individuals.

Tourism Supply Efficiency: An Analysis of Countries in the Asia-Pacific Region

The objective of this research is to analyze the factors affecting the tourism supply and its efficiency of the tourism supply for countries in the Asia-Pacific region. The method uses the stochastic frontier with Maximum Likelihood Estimation (MLE) analyzed by Frontier software. 4.1. The data were collected from panel data from 2010 - 2019 for 23 countries. The results of the study revealed that 1) Tourism investment from the private sector and timing factors positively affect the tourism supply of countries in the Asia-Pacific region, while the tourism labor value factor has a negative effect on the tourism supply of countries in the region 2) For the technical performance measurement of tourism supply in each sub-region in the Asia-Pacific region, the average is between 0.387 and 0.657. East Asia shows the highest technical efficiency in China, Hong Kong, Japan, Macau and Mongolia while South Asia has the lowest technical efficiency in Bangladesh, India, Nepal, Pakistan, Sri Lanka and the Maldives, respectively.

UTILIZATION OF STUDENT’S T DISTRIBUTION TO HANDLE OUTLIERS IN TECHNICAL EFFICIENCY MEASUREMENT

Stochastic frontier analysis (SFA) is the favorite method for measuring technical efficiency. SFA decomposes the error term into noise and inefficiency components. The noise component is generally assumed to have a normal distribution, while the inefficiency component is assumed to have half normal distribution. However, in the presence of outliers, the normality assumption of noise is not sufficient and can produce implausible technical efficiency scores. This paper aims to explore the use of Student’s t distribution for handling outliers in technical efficiency measurement. The model was applied in paddy rice production in East Java. Output variable was the quantity of production, while the input variables were land, seed, fertilizer, labor and capital. To link the output and inputs, Cobb-Douglas or Translog production functions was chosen using likelihood ratio test, where the parameters were estimated using maximum simulated likelihood. Furthermore, the technical efficiency scores were calculated using Jondrow method. The results showed that Student’s t distribution for noise can reduce the outliers in technical efficiency scores. Student’s t distribution revised the extremely high technical efficiency scores downward and the extremely low technical efficiency scores upward. The performance of model was improved after the outliers were handled, indicated by smaller AIC value.

КОНЦЕПТУАЛЬНИЙ ПІДХІД ДО МЕТРОЛОГІЧНОГО ЗАБЕЗПЕЧЕННЯ СТВОРЕННЯ КОМПОЗИТНИХ КОНСТРУКЦІЙ ЦИВІЛЬНИХ ЛІТАКІВ

A conceptual approach to the metrological support of the creation of composite structures for civil aircraft units has been developed and substantiated.It is shown that polymer composite materials currently occupy a significant place in the structures of civil aircraft and the volume of their effective use is constantly increasing, reaching in some cases 50% of the weight of the airframe, which indicates the relevance of the problem of metrological scientific support for creating structures of this class.The main goals of metrological assurance have been revealed, including the requirements for the uniformity and accuracy of measurements, the sufficiency and reliability of effective control, high quality measurements, as well as reducing the time and cost of research and experiments, metrological reliability, reducing the range of used measuring instruments, improving the safety of working conditions and environmental protection.At all stages (stages) of the existence of an aircraft, the effectiveness of structures made of PCM is ensured by various methods, methods and technical means of metrology. The main components of quality assurance are considered, which, being different in nature (process, property, form of conformity, set of devices, science), are integrated into a single system of concepts that form (ensure) the quality of an object.A block diagram of the main quality assurance tools is proposed, including certification, standardization, technical measurements, interchangeability and metro logic, as well as a block diagram of the general characteristics of the measurement quality. It is shown that these block diagrams together form the concept of scientific support for the creation of efficient structures of composite aircraft assemblies.It is proposed to form the development of this concept on the basis of the developed complex criterion for the effectiveness of the use of polymer composites in the environments of production, technological and scientific support.The structure of research is determined on the basis of the proposed conceptual approach to metrological support for the creation of composite structures of civil aircraft units at the main stages of their life cycle

Measurements and observations of movements at work on warehouse forklift truck operators

Inclinometry and video analyses can provide objective measures of physical workloads. The aim was to measure and observe arm, back, and head postures and movements among forklift truck operators (FLTOs) during a work day, analyzing differences between types of forklift trucks and to assess reported work load and health. Twenty-five male FLTOs at a high-level warehouse were randomly included. The data collected comprised technical measurements, video analyses of postures and movements, and a questionnaire measuring health, pain, and workload. On average, the FLTOs rotated their head more than 45 degrees, 232 times/hour. The video analysis revealed that FLTOs periodically drive the forklift truck sideways with the head rotated in the direction of travel, and in periods look upwards, in which the head is highly rotated and extended. Inclinometry and observations during the working day has a potential to be a valuable part of risk assessment promoting occupational safety and health.

О качестве измерений кожно-жировых складок калиперами и скользящим циркулем

A comparative study of the calipers GPM (DKSH, Switzerland), Holtain (Holtain Ltd, Great Britain), the caliper designed by V.E. Deryabin, and the sliding caliper GPM (Martin type) was carried out by the four measurers. The study was conducted using a metal caliper checking gauge GPM, a ‘sandwiches’ of soft silicone rubber kSil™ GP250 (Silicon Engineering, UK), as well as by measurements of subscapular, triceps, suprailiac, and calf skinfolds utilized in the Heath-Carter somatotype assessment scheme, in 20 adult volunteers (10 women and 10 men). Results and discussion. When measuring the caliper checking gauge, the V.E. Deryabin’s and the sliding caliper were accurate, the caliper GPM slightly underestimated (by 0.2 mm), and the caliper Holtain overestimated the exact values (by 0.4-0.6 mm). When measuring ‘sandwiches’ of silicone rubber, the GPM and Holtain calipers showed small but statistically significant differences between measurers (up to 1.4 mm), and for the V.E. Deryabin’s caliper, these differences were more pronounced (up to 5 mm). With a sufficiently high reproducibility of skinfold data, the mean values of their total thickness for the GPM and Holtain calipers differed significantly, and for the V.E. Deryabin and GPM calipers, there were no significant differences. The measurement data using the sliding caliper were consistent with those for the Holtain caliper but showed the largest variation of data between measurers: the maximal difference of the total skinfold thickness averages was 5.2 mm and 7.1 mm in the female and male subgroups, respectively, or 10-14% of the total averages. Conclusion. The results obtained support the need for mutual comparison of skinfold calipers and control of technical measurement errors to ensure data comparability. Cross-calibration of skinfold calipers is a necessary procedure that should precede the anthropometric study. When measured by an experienced anthropologist, the technical error of measuring skinfolds with a sliding caliper can be reduced, but this instrument is not recommended for training and subsequent use for skinfold measurements due to the high risk of obtaining inconsistent data.

Production and scale efficiency of South African water utilities: the case of water boards

AbstractSouth Africa is a water scarce country with deteriorating water resources. Faced with tight fiscal and water resource constraints, water utilities would have to adopt technically efficient water management technologies to meet developmental socio-economic objectives of universal coverage, aligned to the United Nation's Sustainable Development Goal 6. It is important to measure the technical efficiency of utilities as accurately as possible in order to inform policy. We do this by using a non-parametric method known as Data Envelopment Analysis to determine, measure, analyse and benchmark the technical efficiency of all water boards in South Africa. Our contribution to the literature is twofold: This is the first paper to model technical efficiency of water boards as utility suppliers and guardians of water services in South Africa, and second, we address the over- and underestimation issues of technical efficiency measurement in the water sector. We do this by modelling one of the most pronounced negative externalities from water provision (water losses) as an undesirable output using the approach developed by You and Yan. We find, on average, technical efficiency of water boards is 49%, with only three of the nine water boards technically efficient. Six of the smaller water boards showed high levels of inefficiency with an inefficiency rate of 51%, which is equivalent to wastage in expenditure of R3.7 billion. Six water boards operate at increasing returns to scale and two are scale efficient. Only Rand and Sedibeng water boards exhibited decreasing returns to scale. Therefore, redirecting potential efficiency savings to optimal uses could result in technical and scale efficiency for the sector. Scale efficiency results seem to support larger regional water boards as small- to medium-sized water boards are scale inefficient with low technical efficiency. For example, Amatola Water (small water board) with an efficiency score of only 16% has a total expenditure of 18% of that of Umgeni (large water board), but sells only 6.7% of the quantity sold by Umgeni. Amatola also has seven times the proportion of water losses compared with Umgeni and charges 1.6 times the tariff of Umgeni. The ratio model with an undesirable output outperforms previous methods to deal with undesirable (bad) outputs, which either provide an over- or underestimation of technical efficiency.

Comparing the Structured Multidisciplinary work Evaluation Tool (SMET) questionnaire with technical measurements of physical workload in certified nursing assistants in a medical ward setting

The Certified Nursing Assistant (CNA) is an important part of the workforce in hospitals and nursing homes, whose work includes heavy and repetitive work tasks including patient manual handling. The Structured Multidisciplinary work Evaluation Tool (SMET) questionnaire is an Occupational Health Service method for evaluation of the work environment. The aim of this study is to compare the SMET questionnaire with technical measurements of physical workload in CNAs in a medical ward setting. 16 CNA's participated voluntarily to 8 h of measurements during one workday. Physical workload was measured with surface electromyography and inclinometers, and the work environment was evaluated with the SMET questionnaire during the same working day. Spearman's rho was used in the statistical correlation analysis between measurements. This study shows strong, statistically significant correlations between the items in the SMET questionnaire and measured physical workload, n CNAs.

Off-The-Shelf Stylus: Using XR Devices for Handwriting and Sketching on Physically Aligned Virtual Surfaces

This article introduces the Off-The-Shelf Stylus (OTSS), a framework for 2D interaction (in 3D) as well as for handwriting and sketching with digital pen, ink, and paper on physically aligned virtual surfaces in Virtual, Augmented, and Mixed Reality (VR, AR, MR: XR for short). OTSS supports self-made XR styluses based on consumer-grade six-degrees-of-freedom XR controllers and commercially available styluses. The framework provides separate modules for three basic but vital features: 1) The stylus module provides stylus construction and calibration features. 2) The surface module provides surface calibration and visual feedback features for virtual-physical 2D surface alignment using our so-called 3ViSuAl procedure, and surface interaction features. 3) The evaluation suite provides a comprehensive test bed combining technical measurements for precision, accuracy, and latency with extensive usability evaluations including handwriting and sketching tasks based on established visuomotor, graphomotor, and handwriting research. The framework’s development is accompanied by an extensive open source reference implementation targeting the Unity game engine using an Oculus Rift S headset and Oculus Touch controllers. The development compares three low-cost and low-tech options to equip controllers with a tip and includes a web browser-based surface providing support for interacting, handwriting, and sketching. The evaluation of the reference implementation based on the OTSS framework identified an average stylus precision of 0.98 mm (SD= 0.54 mm) and an average surface accuracy of 0.60 mm (SD= 0.32 mm) in a seated VR environment. The time for displaying the stylus movement as digital ink on the web browser surface in VR was 79.40 ms on average (SD= 23.26 ms), including the physical controller’s motion-to-photon latency visualized by its virtual representation (M= 42.57 ms,SD= 15.70 ms). The usability evaluation (N= 10) revealed a low task load, high usability, and high user experience. Participants successfully reproduced given shapes and created legible handwriting, indicating that the OTSS and it’s reference implementation is ready for everyday use. We provide source code access to our implementation, including stylus and surface calibration and surface interaction features, making it easy to reuse, extend, adapt and/or replicate previous results (https://go.uniwue.de/hci-otss).

A top-down measure of gene-to-gene coordination for analyzing cell-to-cell variability

Recent technological advances, such as single-cell RNA sequencing (scRNA-seq), allow the measurement of gene expression profiles of individual cells. These expression profiles typically exhibit substantial variations even across seemingly homogeneous populations of cells. Two main different sources contribute to this measured variability: actual differences between the biological activity of the cells and technical measurement errors. Analysis of the biological variability may provide information about the underlying gene regulation of the cells, yet distinguishing it from the technical variability is a challenge. Here, we apply a recently developed computational method for measuring the global gene coordination level (GCL) to systematically study the cell-to-cell variability in numerical models of gene regulation. We simulate ‘biological variability’ by introducing heterogeneity in the underlying regulatory dynamic of different cells, while ‘technical variability’ is represented by stochastic measurement noise. We show that the GCL decreases for cohorts of cells with increased ‘biological variability’ only when it is originated from the interactions between the genes. Moreover, we find that the GCL can evaluate and compare—for cohorts with the same cell-to-cell variability—the ratio between the introduced biological and technical variability. Finally, we show that the GCL is robust against spurious correlations that originate from a small sample size or from the compositionality of the data. The presented methodology can be useful for future analysis of high-dimensional ecological and biochemical dynamics.

Multichannel gas electron multiplier based soft x-ray field-programmable gate array measurement system for W-Environment in Steady-state Tokamak (WEST): Hardware, installation, and first plasma acquisition.

The work describes a novel approach to the design of a fast, multichannel measurement system for plasma diagnostics [A. Wojenski et al., Fusion Eng. Des. 123, 727 (2016)]. Its main scope is to provide measurements of soft X-ray (SXR) emission during plasma phenomena at the W-Environment in Steady-state Tokamak (WEST), especially for monitoring and tracing tungsten impurities. This paper describes the vertical Gas Electron Multiplier (GEM) camera installed at the WEST [M. Chernyshova et al., J. Instrument. 10, P10022 (2015)]. The designed GEM detector readout board has more than 100 channels, resulting in high-performance requirements for the data acquisition and processing system. The novel system construction approach is that the unit works on the raw signals providing a high quality of the data, especially in the scope of pileup effect analysis. In the case of doubtful results, the source data can be easily reviewed offline. The data selection and transmission are done in Field-Programmable Gate Arrays (FPGAs) on the custom boards with the custom Peripheral Component Interconnect (PCI)-Express Gen2 switch that allows us to register signals from multiple FPGAs and then process the data by complex algorithms [G. Kasprowicz et al., J. Fusion Energy 38, 480 (2019)]. The firmware is replaceable and different working modes can be applied (some under verification): global trigger mode, high-speed data serialization, and extended signal registration. Low level optimized central processing unit software for data readout was also designed [P. Linczuk et al., J. Instrum. 14, C05001 (2019)]. The installation of the system is described due to complex system components' distribution. The first results of the successful acquisition of the plasma at the WEST are discussed. The corresponding SXR energy and topology spectra were computed. Those are the first technical measurements of the system to ensure verification of data quality.

Failure Mechanisms of the Wellbore Mechanical Barrier Systems: Implications for Well Integrity

Abstract Energy sustainability is the main motive behind the evolution of the concept of well integrity in the oil and gas industry. The concept of well integrity adopts technical, operational, environmental, organizational, and safety measurements to secure the energy supply throughout the life of the well. Technically, a high quality well performance can be maintained by establishing robust barrier systems that are responsible for preventing, controlling, and mitigating potential risks that could arise during the well life cycle. A barrier system is conventionally nested from one or multiple elements that act individually or collectively to scaffold the well integrity. The protection layers in a wellbore can be lost if the integrity of the barrier system is compromised according to the failure of one or all of its elements. Failure can be triggered by technical or non-technical factors. In this study, technical aspects that drive barrier failure mechanisms have given more emphasis. The failure mechanisms of the key mechanical barrier systems, such as casing strings, cement, diverters, blowout preventers (BOPs), production stream valves, and seal assemblies, have been thoroughly investigated. In this study, a comprehensive review of barriers failure mechanisms has been conducted to identify the roots of failures and to outline some of the essential safety measures adopted to avoid the loss of well control. The major findings of this paper revealed that well barrier systems are highly susceptible to failure in unconventional reservoirs, deep and ultra-deep offshore wells, and geothermal wells. The predominant failures identified are casing collapse resulting from cyclic loads, cement percolation by gas migration, cement carking by hoop stress, BOPs wear and tear promoted by frequent tests, and elastomeric materials disintegration caused by acidic gases. Considering these failure mechanisms while designing a wellbore can help the engineers improve the construction quality. In addition, it can assist the operation and maintenance crews in optimizing safe operation boundaries.

Nonlinearity of intracochlear motion and local cochlear microphonic: Comparison between guinea pig and gerbil

Studying the in-vivo mechanical and electrophysiological cochlear responses in several species helps us to have a comprehensive view of the sensitivity and frequency selectivity of the cochlea. Different species might use different mechanisms to achieve the sharp frequency-place map. The outer hair cells (OHC) play an important role in mediating frequency tuning. In the present work, we measured the OHC-generated local cochlear microphonic (LCM) and the motion of different layers in the organ of Corti using optical coherence tomography (OCT) in the first turn of the cochlea in guinea pig. In the best frequency (BF) band, our observations were similar to our previous measurements in gerbil: a nonlinear peak in LCM responses and in the basilar membrane (BM) and OHC-region displacements, and higher motion in the OHC region than the BM. Sub-BF the responses in the two species were different. In both species the sub-BF displacement of the BM was linear and LCM was nonlinear. Sub-BF in the OHC-region, nonlinearity was only observed in a subset of healthy guinea pig cochleae while in gerbil, robust nonlinearity was observed in all healthy cochleae. The differences suggest that gerbils and guinea pigs employ different mechanisms for filtering sub-BF OHC activity from BM responses. However, it cannot be ruled out that the differences are due to technical measurement differences across the species.

Beyond métiers: social factors influence fisher behaviour

Abstract Fisheries management is usually supported by technical and financial measurements (i.e. logbooks and market data), which are helpful for ecological or economic assessments. Yet this information is not able to address social heterogeneity and fisher motivations, which are key to understanding fisher behaviour. This case study of the demersal segment in the Netherlands shows that combining quantitative analysis of logbooks with qualitative data collected by engaging with fishers can capture both fishing activity and its motivations, generating a more social understanding of fisher behaviour. A métier analysis of logbook data describes five dominant fishing practices among the selected segment. Twenty-five in-depth interviews with fishers along with focus groups including other experts identify three social factors that influence fisher behaviour in the Dutch demersal fleet: business structure, working rhythm, and polyvalence. The results show that motivations for fisher behaviour are more complex than complying with regulations or seeking profit: social factors also influence fishing activity. Furthermore, these social factors have real implications for the impacts of management measures on both the fishing communities and the environment, especially in times of change. These results are useful for management strategy development or evaluation because they are feasibly observable through existing data collection protocols.

Elemental Composition in Female Dry Femora Using Portable X-Ray Fluorescence (pXRF): Association with Age and Osteoporosis.

Pathophysiological conditions can modify the skeletal chemical concentration. This study analyzes the elemental composition in two anatomical regions from dry femoral bone using a portable X-Ray Fluorescence (pXRF) and evaluates its impact in the bone mineral density (BMD). The left femora of 97 female skeletons (21-95years old individuals) from the Coimbra Identified Skeletal Collection were studied. Diagenetic biases were discarded at the outset and BMD was determined with Dual-energy X-ray absorptiometry. Chemical measurements were performed at the midpoint of the femoral neck and at the midshaft using a pXRF device, and comparisons were made considering the age and the BMD values. Only elements with a Technical Measurement Error ≤ 5% were selected: P, S, Ca, Fe, Zn, As, Sr, Pb and the Ca/P ratio. Statistically significant differences were found between regions, with higher concentrations of P, Ca, Zn and S at the midshaft, and the Ca/P ratio at the femoral neck. The concentration of P is higher in individuals < 50years, while S and Ca/P ratio increase in individuals ≥ 50years. The decrease of P with age can be simultaneously related to the decline of its concentration in osteoporosis. Decreased BMD is also associated with higher levels of S and Pb. Osteoporosis enhances the absorption of osteolytic elements in specific locations. This fast and non-destructive technique has proved effective for the comprehension of chemical changes related to bone mass loss. This study highlights the potential of identified skeletal collections to improve the knowledge about bone fragility.

Effectiveness of plyometric or blood flow restriction training on technical kick force in taekwondo

Introduction. The aim of this study was to understand the effect of blood flow restriction (BFR) and plyometric training methods on the development of taekwondo technical kick force in active taekwondo athletes. Material and Method. 31 taekwondo athletes, aged between 15 and 18 years, voluntarily participated in the study. They were divided into the blood flow restriction, plyom-etric training and control groups. In addition to taekwondo training, blood flow restriction and plyometric training group were trained for 6 weeks. Technical strike force measurements were made with Herman Digital Trainer, placed on the Hasedo. The difference was examined by the paired sample t-test. Comparison of three groups was made with a use of the Friedman test. Re-sults. Statistically significant pre- and post-test differences were found in all technical impact strength values except Tolyochagi right leg in groups participating in BFR training. The difference in the right and left foot and palding kick, the right foot tolyochagi kick, and the right-left foot dwitchagi stroke was statistically significant only in the BFR training group. Conclusions. Con-sidering the effective development of the BFR method on technical strike force in Taekwondo athletes, it is thought that adding the BFR method to routine taekwondo training under the su-pervision of an expert will positively contribute to success.

Intangible assets and the efficiency of manufacturing firms in the age of digitalisation: the Russian case

AbstractA wide consensus exists on the role of intangible assets in both developed and developing economies, especially now, with the new generation of information and communication technologies. Emerging economies generally demonstrate lower endowment with intangibles (Dutz et al., 2012), but follow the same positive patterns for long-run development. In Russia, the contribution of intangibles to growth is still modest, and its capacity to foster productivity has not been achieved. As previous studies showed, efficiency represents one of the main channels of total factor productivity growth. This paper studies the effects of intangibles on the efficiency of Russian manufacturing firms in 2009–2018. Considering the heterogeneity of sectors and firms, the stochastic frontier model is applied. In general, the impact of intangibles is positive but small and influenced by external shocks and structural features. The paper provides evidence on different contributions of intangibles to efficiency for high-tech and low-tech firms and its change over time. It contributes to the strand of literature regarding the technical efficiency measurement on the microlevel. On the practical side, the paper suggests an analytical framework for differentiated policy mechanisms to drive investments in intangibles, which are essential for current digital transformation.