Coordinate Values Research Articles

Spatial-Temporal Patterns of Ecosystem Services Supply-Demand and Influencing Factors: A Case Study of Resource-Based Cities in the Yellow River Basin, China

The aim of this study was to reveal the spatiotemporal pattern of the supply and demand of ecosystem services (ESs), as well as the significant driving factors for understanding the impact of human activities on the natural ecosystem. To provide a scientific basis for formulating regional sustainable development strategies that enhance human well-being, resource-based cities in the Yellow River Basin (YRB) were selected as the case study. The supply and demand of ecosystem services in these cities from 2000 to 2020 were measured. The spatiotemporal evolution of the supply-demand relationship was illustrated by taking its coordination degree. In addition, geographical detector and geographically weighted regression (GWR) models were applied to quantify the spatiotemporally varying effects of natural and socioeconomic factors on the ES supply--demand relationship. The results showed that resource-based cities in the YRB were experiencing expansion in supply and demand overall, but the supply-demand relationship tended to be tense. The northwest YRB had higher coordination values of supply-demand, while lower values were found in the southeast YRB. Moreover, the relationship between supply and demand was significantly affected by natural and socioeconomic factors, such as elevation, slope, precipitation, land-use type, population density, and gross domestic product (GDP) per land. Furthermore, the GWR model suggested that the effects of driving factors on the supply-demand relationship had notable spatial heterogeneity. The coordination of ES supply-demand in the resource-based cities of southeast YRB was mainly influenced by socioeconomic factors, while that of the west YRB was mainly influenced by natural factors. Our study suggested that it is necessary to enhance the awareness of environmental protection, pay attention to ecological restoration, and avoid unreasonable human disturbance to the ecosystem.

Analysis of Physical Activity in Atoni Meto Traditional Sports on North Central Timor Regency

The purpose of the study was to determine the physical activity and traditional sports of Atoni Meto in North Central Timor Regency. The initial stage of the research method is that researchers develop research instruments that will be used to explore information from sources in depth through direct observation (observation), in-depth interviews, focus grup discussion, and documentation studies to find physical activities and traditional sports Atoni Meto "Mantika" in North Central Timor Regency. In the data analysis process, the research team was based on the Miles and Huberman analysis model: data collection, data reduction, data presentation, and conclusion drawing (verification). The results showed that the physical components contained in the traditional Atoni Meto sport in North Central Timor Regency were the values ​​of sportsmanship, endurance, strength, coordination, balance, and accuracy. Some of these sports components can be integrated into the learning process of Physical Education in Sports and Health at the elementary, middle, and high school levels.

Assessing the damage caused by deer on young trees in a Sugi (Cryptomeria japonica) plantation based on field signs

ABSTRACT Predicting the level of damage by deer browsing in young plantations is important for considering damage control measures. In this study, we examined a method for assessing the level of deer damage in young Sugi (Cryptomeria japonica) plantations with deer-proof fences by observing field signs of deer. First, a questionnaire survey was conducted to obtain information about the damage by deer browsing on planted trees and the extent of field signs, such as browsing marks and deer fecal pellets around the young plantations. The extent of field signs was recorded as qualitative data (i.e. “None”, “A few”, and “Many”). A multiple correspondence analysis (MCA) revealed a relationship between the extent of deer damage in young plantations and the presence of five field signs (browsing marks, bark stripping marks, fecal pellets, trails and tracks) around the young plantations. Based on coordinate values of each field sign obtained using the MCA, the extent of each field sign was scored, and the total value was calculated as the deer impact score (DISco). When the relationship between the DISco and the extent of deer damage to planted trees was subjected to a logistic regression analysis (LRA), the DISco was found to be a significant explanatory variable and the LRA was an effective model (AUC of 0.7809 and 0.7048, respectively) for predicting the probability of stand damage and High stand damage. Therefore, the DISco was shown to be an effective tool for assessing the damage risk of deer in young Sugi plantations with deer-proof fences.

The Coupling Coordination between the Competitiveness Level and Land Use Efficiency of Green Food Industry in China

With the development of the green food industry, land conflicts are gradually escalating, and the coordinated development of competitiveness level and land use efficiency is crucial to the green food industry. The competitiveness level of China’s green food industry at the provincial level between 2011 and 2020 was measured by constructing an index system using the entropy method and VlseCriterion Optimisation and Compromise Resolution (VIKOR) method, and then the land use efficiency was evaluated using the super efficiency Slacks-based Measurement (SBM) model, and the coupling coordination degree was analyzed using the coupling coordination model based on the results of both measurements. The results showed that the competitiveness level of the green food industry was “high in the west and low in the east”; most provinces and cities were with the middle competitiveness level. Land use efficiency generally showed a trend of rising and then falling and leveling off, and the average value of the three regions was ranked as eastern (1.13) > western (0.84) > middle (0.63). The mean value (0.82) of the overall coupling coordination in China floated at the boundary of high-quality coordination, and all three regions showed a trend of rising and then falling and leveling off, and the number of provinces and cities in high-quality coordination in China was shifting from the north to the south during 2011–2020. This study can provide theoretical support for the coordinated development between industrial development and land use, and provide feasible suggestions for the intensive and efficient use of resources.

Visualization and dermatoglyphics of latent fingerprints (sweat pores): Security ink for anticounterfeiting labels and case studies

In this report, 1,8-naphthalimide (NG)-based blue emitters non-covalently doped on silica was used for visualization of latent fingerprints and anticounterfeiting applications. The NG possess CIE coordinate value x = 0.2, y = 0.32 with blue-green emission in solid state and possess low cytotoxicity with IC50 value 85 µM. The excellent performance of NG@SiO2 was demonstrated by visualization of LFPs up to levels 1–3 on a variety of substrates including porous and nonporous surfaces using powder dusting method without any post treatment. The details of level 1 (classification); level 2 (19 minutiae points such as bifurcations, hook, eye, delta, bridge, crossover, lake, island, ridge incipient, scar and speciality features) and level 3 (size, shape, number and position of sweat pores, width of the fingerprint ridge) are clear. A detailed case studies have been carried out by collecting fingerprints from 14 subjects aged between 19 and 29 years. Each collected LFPs were screened and differentiated from each other to establish the individuality of subjects using information of levels 1–3, The NG was further used for developing invisible security ink for use in pen, stamp pad for writing/stamping on paper and silica-coated TLC plates. These results may find applications in forensic science and data security.

Development of an Integrated Water Resource Scheduling Model Based on Platform Plug-In: A Case Study of the Wudu Diversion and Irrigation Area, China

Integrated water resource scheduling is a key strategy for controlling river floods as well as for promoting the benefits and abolishing the harmful aspects of water conservancy projects. It is necessary to explore an effective development mode to address the current issues of long development times and poor outcomes for integrated water resource scheduling models. Drawing on the concept of software reuse, a development mode for an integrated water resource scheduling model is offered based on “platform system + model plug-in”, the cores of which are plug-in modules and interface integration. The boundaries and connection relations of each plug-in module are formed based on the logical analysis of the model plug-in. A web application mode is used to implement a standardized interface, which can be quickly and seamlessly connected to the system platform. The model is explored and applied in the Wudu diversion and irrigation area in China. The generated model is eventually verified using data obtained from two flood periods. According to the simulation results, the gate operation will be convenient, and the target water level will be attained in the allocated time with a satisfactory peak-clipping effect. It shows both good coordination and great utilization value of the plug-in modules. The concept of designing a plug-in database is eventually taken into consideration for combining and generating an optimization model of each river.

Study on the Evolution and Coupling Coordinated Development of Passenger and Freight Transport Network of New Western Land-Sea Corridor

Based on the associated network of passenger and freight transport in the New Western Land-Sea Corridor, the structure and characteristics of passenger and freight transport network in different years are analyzed using passenger volume and freight volume, and the resilience of the network is analyzed using the disturbance model. Finally, the coordinated development of passenger transport and logistics is discussed by applying a coupling coordination model. The results show that, from 2000 to 2018, the New Western Land-Sea Corridor has realized the evolution of the spatial pattern of passenger transport network from “two center and numerous branches” to “three centers and three auxiliaries”. Moreover, the evolution of the spatial pattern of the freight transport network changed from “two centers and one auxiliary” to “one center and multiple auxiliaries”. In terms of network tenacity, the disturbance strategy based on node degree value has the strongest damage to the performance of passenger and freight transport networks. The coupling coordination value is gradually rising from a low level and finally develops to an ordered trend. Therefore, it is proposed that passenger transport development could be supported from the “growth pole” and “zone” development modes, while the logistics development would adopt the “axis” development pattern and focus on the protection of the vital city nodes in the corresponding network. In this way, it can realize the effective connection of multiple paths, improve the tenacity of network and boost hub economy, consummate the regional coordination mechanism, and finally promote the advancement of the New Western Land-Sea Corridor.

Research on Data Fusion of Positioning System with a Fault Detection Mechanism for Autonomous Vehicles

A positioning system provides useful positioning information for applications. The ability to maintain high-quality positioning information in real time is crucial. Autonomous vehicles require positioning information to plan control strategies. Inadequate positioning accuracy affects control and safety. This article explores the effect of an error detection and correction method on coordinate information fusion. This method can be used to efficiently correct positioning errors in the presence of faults. The fault detection mechanism is not limited to positioning systems with certain types of sensor applications. and it has certain flexibility in various applications. This positioning system detection method uses more than two positioning systems. Primarily, one positioning system is used to monitor the other. When the error of the positioning system differs excessively from the system setting value, the positioning fusion algorithm will make appropriate adjustments to output the corrected coordinate value. Therefore, this method integrates different positioning technologies, including a global position system (GPS), simultaneous localization and mapping (SLAM), inertial measurement units (IMUs), and mileage meters. Autonomous vehicles already have the required sensors deployed, and our method can be implemented at no additional cost. We integrated two positioning systems to support the positioning applications and designed a fault detection method to detect errors in the positioning system. This allowed the system to have some reference information by which to correct the coordinate information. According to the experimental findings, positioning information errors were corrected at a rate of 89.8%. The positioning system with the added detection function was able to effectively filter the data without too many errors. Additionally, the results showed that this method can effectively correct positioning errors. The results indicate that adding an error detection mechanism can effectively improve the accuracy of coordinate data fusion. Positioning systems with an error detection function can thus improve applications’ performance.

Collection of IDHEAS-based human error probability data for nuclear power plant commissioning through expert elicitation

Human error probability (HEP) is one of the most important indicators to assess human reliability. In this study, we collected nominal HEP (NHEP) data for nuclear power plant commissioning through a formal expert elicitation process. Cognitive failure modes (CFMs) were adapted from the Integrated Human Event Analysis System (IDHEAS) method, and included three different detail levels. Obtained NHEP values for detection, understanding, action execution, and inter-team coordination seem to be consistent with those in IDHEAS-ECA, while the NHEP for decision-making is significantly lower than that in IDHEAS-ECA. Several challenges have been identified, which are related with the IDHEAS-based CFMs and the expert elicitation process. Because the IDHEAS-based CFMs are technology neutral and reflect the failures of human cognition, the obtained NHEP values could be applicable in other application domains.

Cool green light emitting GdAlO3:Tb3+ perovskite nanomaterials: Crystal structure and spectroscopic characteristics for advance display appliances

Using the gel-combustion process, pure-phase GdAlO3 (GAP) perovskite phosphor doped with different concentration of Tb3+ ion has been synthesized. XRD, TEM, FTIR, PL/PLE and fluorescence decay studies were used to characterize the materials in detail. On the basis of powder XRD data, phase evolution of perovskite material with respect to the various content of trivalent terbium ion has been examined, and the rietveld technique has been used to further refine the structural characteristics of the orthorhombic phase. Among all the samples, nanosample (x = 0.05, known as optimized sample) was found with high crystallinity and intensity and further their calcination effect was also investigated. TEM investigation revealed the formation of nanoparticles with some agglomeration. When excited at 272 nm, a series of characteristic emissions bands of Tb3+ doped GdAlO3 phosphors were detected in the emission spectra at about 492 nm, 542 nm, 589 nm, and 624 nm, which resemble to the 5D4→7F6, 5D4→7F5, 5D4→7F4, and 5D4→7F3 transitions, individually. The most intense band detected at 542 nm (5D4→7F5) is responsible for the green color in the synthesized material. The lifetime of Tb3+ emission was determined to be gradually declining with concentration of Tb3+ ions using fluorescence decay analysis. The derived values of CIE chromaticity coordinates (x, y) were quite closer to the NTSC standard value of green emission which further validates their applicability in display application and other lighting foundations.

Математическая модель задатчика перемещения электропривода и разработка его программного обеспечения

Various computational algorithms to perform automatic control of motion are widely used in microprocessor control systems of electric drives. The requirements for such algorithms are the minimum execution time, the minimum amount of calculations, the compactness of the software, the convergence in the statics and dynamics of the control system. It ensures the stability and accuracy of coordinates control. The above-mentioned issues are applicable to the computational algorithm to develop a S-shaped trajectory of the electric drive by the position master unit. The position master unit based on the well-known mathematical model has some disadvantages that limit its use. They are incorrect calculation of the trajectory depending on the speed, acceleration, and sampling interval, as well as the self-oscillatory processes in case of the output and intermediate coordinates. As a result, it leads to a decrease of the accuracy of the electric drive control. Despite the standard solutions, such position master unit require improvement. In this regard, upgrading such a position master unit is relevant. The aim of upgrading is to eliminate these shortcomings by introducing corrective calculations and logical sequences that transfer the position master unit into a stable state as soon as it reaches a given value of the output coordinate. To control the motion of the electric drive when we develop a mathematical model and software based on it, it is necessary to use computational algorithms and numerical methods of calculation that are the least costly in terms of execution time. A modernized mathematical model of the S-shaped trajectory of position master unit is proposed. Restrictions of the parameters of this master unit have been eliminated. They may lead to incorrect path generation, as well as self-oscillations of the output and intermediate coordinates during the path generation, which reduces the accuracy of the electric drive control and cause vibration and noise. The software of the modernized position master unit, in comparison with its original form, does not contain cumbersome arithmetic that is costly in terms of execution time. The software has been successfully implemented into the microprocessor control system of the electric drive. At the same time, it is necessary to observe a time-stable execution of computational sequences and to consider the influence of the values of the numerical parameters used in the calculations.

Combining Dilution of Precision and Kalman Filtering for UWB Positioning in a Narrow Space

Affected by the spatial environment, the accuracy and stability of ultra-wideband (UWB) positioning in a narrow space are significantly lower than those in the general indoor environment, which limits navigation and positioning services in a complex scene. To improve the positioning accuracy and stability of a narrow space, this study proposed a positioning algorithm by combining Kalman filter (KF) and dilution of precision (DOP). Firstly, we calculated the DOP values of the target narrow space by changing the location of the test nodes throughout the space. Secondly, the initial coordinate values of the test nodes were calculated by the weighted least squares (WLS) positioning algorithm and were used as the observation values of KF. Finally, the DOP values were adaptively introduced into KF to update the coordinates of the nodes to be tested. The proposed algorithm was tested in two narrow scenes with different length–width ratios. The experimental results showed that the DOP values of the narrow space were much higher than that of the wide space. Furthermore, even if the ranging error was low, the positioning error was high in the narrow space. The proposed fusion positioning algorithm reported a higher positioning accuracy in the narrow space, and the higher DOP values of the scene, the greater the accuracy improvement of the algorithm. This study reveals that no matter how the base stations are configured, the DOP values of the narrow space are much higher than that of the wide space, thus causing larger positioning errors. The proposed positioning algorithm can effectively suppress the positioning error caused by the narrow spatial structure, so as to improve the positioning accuracy and stability.

Penentuan Alternatif Strategi Pemasaran dengan Pendekatan Analisis SWOT melalui Faktor Internal dan Faktor Eksternal pada Peningkatan Pendapatan UMKM KUBE (Kelompok Usaha Bersama) Mega Buana di Masa Pandemi Covid - 19

This study aims to analyze the marketing strategy of Kube Mega Buana UMKM and analyze the application of accounting information systems to increase the income of Kube Mega Buana UMKM during the covid 19 pandemic. This type of research is quantitative and qualitative descriptive with data collection techniques, namely observations, interviews, literature studies, and distributing questionnaires with a total sample of 25 respondents who are members of Kube Mega Buana UMKM for strategy assessment. The results of this study indicate that Kube Mega Buana is in Quadrant I position with values ​​(X = 1.44) and (Y = 1.23) which explains that UMKM Kube Mega Buana has great opportunities and strengths so that they can take advantage of existing opportunities with a value of The highest coordination of S-O strategy was 4.71, with alternative strategies produced, namely innovating pineapple products and packaging forms, maintaining relationships with partners, utilizing digital marketing technology advances in marketing, and maintaining the quality of raw materials.

A real-time driver fatigue identification method based on GA-GRNN.

It is of great practical and theoretical significance to identify driver fatigue state in real time and accurately and provide active safety warning in time. In this paper, a non-invasive and low-cost method of fatigue driving state identification based on genetic algorithm optimization of generalized regression neural network model is proposed. The specific work is as follows: (1) design simulated driving experiment and real driving experiment, determine the fatigue state of drivers according to the binary Karolinska Sleepiness Scale (KSS), and establish the fatigue driving sample database. (2) Improved Multi-Task Cascaded Convolutional Networks (MTCNN) and applied to face detection. Dlib library was used to extract the coordinate values of face feature points, collect the characteristic parameters of driver's eyes and mouth, and calculate the Euler Angle parameters of head posture. A fatigue identification model was constructed by using multiple characteristic parameters. (3) Genetic Algorithm (GA) was used to find the optimal smooth factor of Generalized Regression Neural Network (GRNN) and construct GA-GRNN fatigue driving identification model. Compared with K-Nearest Neighbor (KNN), Random Forest (RF), and GRNN fatigue driving identification algorithms. GA-GRNN has the best generalization ability and high stability, with an accuracy of 93.3%. This study provides theoretical and technical support for the application of driver fatigue identification.

Emerging green light emission of Er3+ -activated single phased GdAlO3 phosphors for lighting applications.

An erbium ion (Er3+ )-activated gadolinium aluminate (GdAlO3 ) nanophosphor was synthesized by utilizing urea assisted gel-combustion method. The crystal structure along with all other crystal parameters was determined by X-ray diffraction (XRD) patterns. The selected samples are of orthorhombic phase with Pnma space group. The agglomerated particles within nanorange have been confirmed by transmission electron microscopy (TEM) micrographs. Elemental investigation was performed by energy dispersive X-ray spectroscopy (EDX). Photoluminescence excitation (PLE) spectrum reveals a strong excitation band corresponding to the gadolinium ion (Gd3+ ) (276 nm) and a band near ultraviolet (UV) absorption for Er3+ (377 nm). Strong excitation band of Gd3+ was evident for the energy transfer between Gd3+ and Er3+ ions. All the doped sampled are excited at 377 nm wavelength. The photoluminescence (PL) spectrum exhibits an intense band at 546 nm (4 S3/2 → 4 I15/2 ) which is responsible for the green emission in the processed samples. The color coordinate values define their color in the green region and correlated color temperature (CCT) values affirm their utility as a cold light source.

Machine learning enables accurate wire loop profile prediction for advanced microelectronics packaging

Increasingly miniaturized device interconnections constantly compress the space in chip packages, forcing the control of wire loop profiles of great significance. A machine learning (ML) wire profile prediction model combining the finite element (FE) simulation and ML algorithms is developed in this study. First, a flat-looping pattern with three kinks is designed to model the wire profile. Thereafter, the relevant database of the wire profile is established by utilizing FE simulation results. After correlation analysis and features redundant of the data, the relationship between the wire bond profile and the three input parameters are modeled, namely, the first reverse angle Ө1, high-span difference TK, and the span K. Subsequently, the ML model trained and optimized through Support Vector Regression (SVR) and Support Vector Machine (SVM) algorithms. The output parameters of the model are the coordinate values of three kinks, among which K1h, K2l, K2h, K3l, and K3h are trained through the SVR regression model, and K1l is trained through the SVM classification model. After hyperparameter optimization, the final high-accuracy prediction model is obtained. This model demonstration proves a viable approach to predicate wire profiles with various spans and heights. The accuracy of model prediction is verified with four sets of actual wires. The mean absolute percentage error of each predicted wire is 6.3 %, 6.4 %, 6.3 % and 7.1 %, respectively. Compared with traditional FE models that take hours for prediction, this ML model can predict a wire profile with high accuracy in a few seconds. The proposed ML model exhibits great potential for wire profile prediction that significantly reduces the wire profile prediction period.

Application of ANN Weighted by Optimization Algorithms to Predict the Color Coordinates of Cellulosic Fabric in Dyeing with Binary Mix of Natural Dyes

Cotton is one of the most important fibers used in the textile industry. The dyeing of cotton with synthetic anionic dyes consumes large amounts of salt and alkali, which makes it a challenge for the environment. Furthermore, the relatively high percentage of synthetic dyes remaining in the dyebath is a potential threat for the environment and human health. The application of plant-derived natural dyes has recently been considered as a promising approach to overcome this problem. Optimization of the dyeing process and prediction of the values of the color coordinates of dyed textiles have always been among the most pronounced challenges in the textile industry, especially when a mixture of dyes or mordants is used. In this study, alum was used for mordanting of cotton and two natural dyes—namely, weld and madder—were used for the dyeing. The samples were dyed with various combinations of mordant, weld, and madder for the weight of the fabric and statistical analysis revealed that all three mentioned parameters were effective in determining the color coordinates. To determine the best model to predict the color coordinates of cotton fabrics, the regression method and ANN models weighted with back-propagation (BP) and optimization algorithms, such as the genetic algorithm, particle swarm optimization, gray wolf optimization, FMINCON (a built-in function of MATLAB software) and a combination of particle swarm optimization and FMINCON (PSO-FMIN), were employed and compared based on the mean squared error (MSE). The obtained results revealed that using the PSO-FMIN algorithm for ANN weighting led to higher accuracy in the prediction of color coordinates. The MSEs obtained for ANN outputs and the corresponding actual values reached 2.02, 1.68 and 1.39 for the l*, a* and b* coordinates, which were 44%, 23% and 26% better than the result obtained with BP, respectively.

Portable Microcontroller-Based Colorimeter For Determining Plant Development Stability

It was shown that the magnitude of fluctuating asymmetry can be used to assess the plant development stability. The shortcomings of the plant physiological state assessment were pointed out, both the visual one and that using the previously created colorimeter. (Research purpose) The study aimed to develop a device for determining the plant development stability by measuring the leaf color. (Materials and methods) The device was tested on cucumber plants grown under different spectra. The surface color was measured on the second and third leaves in the order of their emergence on the plant, to the left and right of the central vein: at the top of the leaf, at the bifurcation of the second veins of the second order, at the base of the leaf. During measurements, the device was brought to the leaf. The principle of the microcontroller-based colorimeter operation was described. (Results and discussion) The asymmetry of the values of the color coordinates of the symmetrical points on the cucumber leaf surface was found to be fluctuating and can be used to assess the plant development stability. The differences in the light environment quality, affecting the plant biometric parameters, are manifested in the asymmetry of the color coordinates of the symmetrical points on the leaf surface and the higher values of growth parameters (in plants under better light environment conditions) correspond to lower values of fluctuating asymmetry. (Conclusions) The developed colorimeter was proved to be compact and ergonomic, easy to manufacture, inexpensive, easy to operate and applicable to the field usage. The device enables to identify differences in the development stability of the plants grown under different light sources. The experimental conditions revealed that the fluctuating asymmetry values were 0.0301 relative units under LEDs and 0.0471 relative units under sodium lamps in the red range. In the green range they were 0.0228 and 0.0305, in the blue one 0.0253 and 0.0416 relative units, respectively.

Scattering of a twisted electron wavepacket by a finite laser pulse

The behavior of a twisted electron colliding with a linearly polarized laser pulse is investigated within relativistic quantum mechanics. In order to better fit the real experimental conditions, we introduce a Gaussian spatial profile for the initial electron state as well as an envelope function for the laser pulse, so the both interacting objects have a finite size along the laser propagation direction. For this setup we analyze the dynamics of various observable quantities regarding the electron state: the probability density, angular momentum, and mean values of the spatial coordinates. It is shown that the motion of a twisted wavepacket can be accurately described by averaging over classical trajectories with various directions of the transverse momentum component. On the other hand, full quantum simulations demonstrate that the ring structure of the wavepacket in the transverse plane can be significantly distorted leading to large uncertainties in the total angular momentum of the electron. This effect remains after the interaction once the laser pulse has a nonzero electric-field area.

Conformally Schwarzschild cosmological black holes

We thoroughly investigate conformally Schwarzschild spacetimes in different coordinate systems to seek for physically reasonable models of a cosmological black hole. We assume that a conformal factor depends only on the time coordinate and that the spacetime is asymptotically flat Friedmann–Lemaître–Robertson–Walker Universe filled by a perfect fluid obeying a linear equation state p = wρ with w > −1/3. In this class of spacetimes, the McClure–Dyer spacetime, constructed in terms of the isotropic coordinates, and the Thakurta spacetime, constructed in terms of the standard Schwarzschild coordinates, are identical and do not describe a cosmological black hole. In contrast, the Sultana–Dyer and Culetu classes of spacetimes, constructed in terms of the Kerr–Schild and Painlevé–Gullstrand coordinates, respectively, describe a cosmological black hole. In the Sultana–Dyer case, the corresponding matter field in general relativity can be interpreted as a combination of a homogeneous perfect fluid and an inhomogeneous null fluid, which is valid everywhere in the spacetime unlike Sultana and Dyer’s interpretation. In the Culetu case, the matter field can be interpreted as a combination of a homogeneous perfect fluid and an inhomogeneous anisotropic fluid. However, in both cases, the total energy–momentum tensor violates all the standard energy conditions at a finite value of the radial coordinate in late times. As a consequence, the Sultana–Dyer and Culetu black holes for −1/3 < w ⩽ 1 cannot describe the evolution of a primordial black hole after its horizon entry.