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Power Line Communications-Artificial Intelligence of Things (PLC-AIoT) combines the low cost and high coverage of PLC with the learning ability of Artificial Intelligence (AI) to provide data collection and transmission capabilities for PLC-AIoT devices in smart parks. With the development of smart parks, their emerging services require secure and accurate time synchronization of PLC-AIoT devices. However, the impact of attackers on the accuracy of time synchronization cannot be ignored. To solve the aforementioned problems, we propose a tampering attack-aware Deep Q-Network (DQN)-based time synchronization algorithm. First, we construct an abnormal clock source detection model. Then, the abnormal clock source is detected and excluded by comparing the time synchronization information between the device and the gateway. Finally, the proposed algorithm realizes the joint guarantee of high accuracy and low delay for PLC-AIoT in smart parks by intelligently selecting the multi-clock source cooperation strategy and timing weights. Simulation results show that the proposed algorithm has better time synchronization delay and accuracy performance.

This study aims to quantitatively assess the adjustment effects of various visual guiding schemes on the abrupt change of vehicle trajectory. A driving simulation experiment was conducted using five simulated scenes: (1) baseline (actual situation), (2) pavement (road studs), (3) low position (flexible guideposts), (4) high position (warning alignment signs and retroreflective arches) and (5) multilayer (combination of all devices). Raw data, including vehicle positions, steering wheel angles and lateral offset, were collected. Based on these data, the gradual change degree of vehicle trajectory (G) and average steering wheel angle (SWAav) were computed to quantitatively evaluate the extent of vehicle trajectory deviation and the stability of steering wheel operations respectively. These two evaluation indicators were then translated into trajectory gradualness (TG) and operation stability (OS), respectively, to assess the adjustment effects of different visual guiding schemes. The study results demonstrate that road studs perform a certain degree of enhancement on operation stability (OS). Flexible guideposts exhibit the best effects on operation stability (OS). Additionally, the combination of warning alignment signs and retroreflective arches demonstrate the best regulation of trajectory gradualness (TG). Multilayer visual guiding system achieves the optimal trajectory gradualness (TG) and operation stability (OS).

In Guizhou Province, there are many coal-bearing structural units, many layers of coal, thin thickness, and most of them are low permeability reservoirs, so it is advisable to adopt the process of “staged fracturing and combined layer drainage and production” to develop coalbed methane. Taking Banguan syncline coalbed methane well as an example, this study analyzed the fracturing effect of two vertical Wells on the basis of the scale of fracturing reconstruction, and then studied the influence of fracturing reconstruction effect on the gas and water production of coalbed methane Wells, and finally summarized the reasonable threshold of efficient fracturing construction parameters of Banguan syncline coalbed methane Wells. The results show that hydraulic fracturing is an effective way to increase permeability of low permeability reservoir, and the permeability increase multiple is closely related to the scale of fracturing reconstruction. The differences of sand addition, liquid addition and single-hole displacement per meter of coal seam between the two Wells of Banguan syncline lead to the permeability ratio of 55∶1 after fracturing reconstruction, and the permeability difference after reconstruction is large. Increasing the liquid addition, sand addition and single hole displacement per meter of coal seam is beneficial to improving the transformation effect of coal seam and gas production. It is recommended that the liquid addition per meter of coal seam should not be less than 400 m3, the sand addition per meter of coal seam should not be less than 20 m3, the fracturing construction displacement should not be less than 8 m3/min, and the single hole displacement should be controlled above 0.2 m3/min. According to the permeability of the coal seam after fracturing and reconstruction, it can be appropriate to quickly discharge and depressurize the coalbed methane Wells with good reconstruction effect. Otherwise, the intensity of discharge and production should be controlled to reduce the sensitivity damage of the reservoir caused by fast discharge and depressurization. The research results can provide technical reference for the permeability and energy improvement of low permeability coal seam in this block.

Multiple and thin coal seams develop in Guizhou province, and the thin coal seams below 1.5 m in the coal measures of Longtan Formation account for more than 50% of the total coal seams. As for the surface gas control technology of thin coal seam mining, there is no single successful surface gas control case of thin coal seam for reference. Based on this, taking YP-7 well in Shanchushu Mine, Guizhou Province as an example, numerical simulation software was used to analyze the influence of fracturing fluid and proppant parameter changes of a single thin coal seam on the reconstruction effect, providing guidance for the optimization of surface fracturing technology of low-permeability thin coal seam gas Wells, and improving the gas extraction and treatment effect. Simulation studies and engineering tests show that fracturing pump displacement and sand ratio have significant effects on reservoir reconstruction. In the fracturing process, the fracturing liquid system of active water +KCL is used to reduce coal seam damage, and the transformation effect of thin coal seam is improved by large liquid volume, medium and high discharge, high sand volume, medium and high sand ratio, slug plus sand, and the permeability of coal seam after fracturing is increased by 6 070 times. In terms of drainage system, combined with mining pressure relief in coal mine, the method of controlling powder production and rapid pressure reduction is implemented to improve the fracturing fluid return rate of low permeability thin coal seam and expand the desorption radius. Within the desorption range of coal seam tons of coal gas decreased by 4.49 m3/t within 6 months of opening and pumping, and it is expected that the coal seam gas content within the pressure fracture network range will be reduced to less than 8 m3/t after opening and pumping for 2 years. The recovery rate of coalbed methane in the corresponding range reached 51.53%. The results show that the pressure is relatively stable during the fracturing process of YP-7 well, and the slight accumulation of quartz sand causes the pressure to rise. However, the plugging can be quickly solved with medium and high displacement, the drainage and production process is continuous and stable, and no sand and powder are produced, and the daily gas volume reaches more than 900 m3. According to the research and practice of comprehensive gas control of surface fracturing and mining pressure relief in this well, it provides guidance for the comprehensive gas control engineering practice of thin coal seam in Guizhou Province.

In order to fully understand the research progress of human factors and traffic safety in curve driving, from the perspective of driver-vehicle-road-environment dynamic traffic system, this paper explored the current research status and development trend of human factors of curve driving, and displayed the development process and structural relationship of human factors research of curve driving by using scientific knowledge map. Through the core collection database of Web of Science, 1408 English literatures related to human factors research of curve driving published from 2012 to 2022 (as of October 1, 2022) were obtained, and the literatures in this field were sorted and analyzed based on the VOSviewer visualization software. The results show that China, Tongji University and Accident Analysis and Prevention are the country, institution and journal with the largest contribution rate in the field of human factors research on curve driving. Co-citation analysis shows that the research contents in this field are divided into 5 clusters: driver's visual characteristics, risk of collision, vehicle dynamics characteristics, the influence of traffic engineering facilities on driving behavior, selection of driving speed. The co-occurrence analysis of keywords shows that the topics of curve geometry design and vehicle dynamics, driving behavior and risk, driving speed and safety, behavior prediction and intervention measures are the current research hotspots in the research field. It is found that the development trend of traffic safety improvement in curves is to construct a continuous, consistent, multi-level visual reference frame conforming to driving expectation through visual guiding technology, and summarizes the technical concept of linear visual guidance. This study can provide a reference for the study of human factors of curve driving.

For urban extra-long underwater tunnels, the obstacle space formed by the tunnel walls on both sides has an impact on the driver's driving. The aim of this study is to investigate the shy away characteristics of drivers in urban extra-long underwater tunnels. Using trajectory offset and speed data obtained from real vehicle tests, the driving behaviour at different lanes of an urban extra-long underwater tunnel was investigated, and a theory of shy away effects and indicators of sidewall shy away deviation for quantitative analysis were proposed. The results show that the left-hand lane has the largest offset and driving speed from the sidewall compared to the other two lanes. In the centre lane there is a large fluctuation in the amount of deflection per 50 seconds of driving, increasing the risk of two-lane collisions. When the lateral clearances are increased from 0.5 m to 2.19 m on the left and 1.29 m on the right, the safety needs of drivers can be better met. The results of this study have implications for improving traffic safety in urban extra-long underwater tunnels and for the improvement of tunnel traffic safety facilities.

The low-permeability characteristic of sandstone-type uranium deposits has become the key geological bottleneck during the in-situ leaching mining, seriously restricting the development and utilization of uranium resources in China. At present, the blasting-enhanced permeability (BEP) and acidizing-enhanced permeability (AEP) are confirmed to be mainstream approaches to enhance the reservoir permeability of low-permeability sandstone-type uranium deposit (LPSUD). To clarify the synergistic effect of BEP and AEP, the acid-rock reaction and dynamic impact experiments were conducted, aiming to study the effect of chemical reactions on pore structure, dynamic mechanical properties and failure pattern of sandstone. Results show that with the increasing acid-rock reaction time, the total pore volume of samples is promoted largely and exhibits obvious chemical damage. The change of pore volume depends on the pore size, the 100–1000 nm and 1000–10000 nm pores are more susceptible to acid-rock reactions. The dynamic peak strength and the dynamic elastic modulus are decreased and the dynamic peak strain and strain rate are increased when lengthening the acid-rock reaction time, whose evolution laws can be fitted by the logistic expression, the linear expression and the exponential expression, respectively. The acid-rock reactions also have an influence on the fracture development of samples after the dynamic impact. The damaged fractures on the end faces of samples grow from the isolated short fracture, the isolated long fracture to the fracture network, and the damaged fractures on the sides of samples develop from the non-penetration fractures, penetration fractures to the multi-branch fractures. This study clarifies the physical and chemical combined damage mechanism, demonstrates the potential of reservoir stimulation by uniting the BEP and the AEP, and provides a theoretical reference for the reservoir stimulation of LPSUD.

The multi-mode communication network provides communication support for the collection, transmission, and processing of energy regulation data and the training of energy regulation models for smart buildings.Digital twin can provide state estimation of computing resources and channel characteristics, assist in the multi-mode communication resource optimization management, and improve the training precision of energy regulation models.However, the digital twin-assisted multi-mode communication resource management of smart buildings still face challenges such as large training error of energy regulation model, coupling of multi-timescale resource allocation, and contradictions between training precision improvement of energy regulation model and energy consumption optimization.Aiming at the above challenges, a multi-timescale communication resource management optimization algorithm based on digital twin and empirical matching learning was proposed.The weighted sum of global model loss function and energy consumption was minimized by jointly optimizing the large-timescale gateway selection and small-timescale channel allocation and power control.Simulation results show that the proposed algorithm can improve the performance of weighted sum of global model loss function and energy consumption, ensure the precise energy regulation requirement and promote the low-carbon operation of smart buildings.

In order to reveal the driving psychological characteristics and influencing factors of drivers under the hairpin curve section, 11 continuous hairpin curves on mountain roads were selected for natural driving test, and the on-board instruments were used to collect the driver’s ElectroCardioGraphy (ECG) under the natural driving habits. Analyse the overall heart rate characteristics, Heart Rate Increase (HRI), Heart Rate Variability (HRV) characteristics of drivers, as well as the relationship between heart rate change and the visual performance of curve corner and slop and curve environment. And compared with the general curve. The results show that: with 180° as the limit, the curve angle of the hairpin curve was divided into 3 types: greater, less or approximate. The 3 types of curve angle have different effects on the driver’s heart rate fluctuations. The overall heart rate distribution can be divided into 2 regions, in which the average heart rate of each driver at the curve, which curve angle ≈ 180°, was higher than the other 2 types of curves. The overall fluctuation range of heart rate in the middle of the curve is at the lowest level in the 3-stage curve segment area. Through the eigenvalue analysis of HRI, it can be seen that the drivers were more susceptible to the external environment when going downhill. When going uphill, the distribution range of the heart rate abnormality value was stable, but the sudden change was obvious. However, during the downhill direction, the overall adjacent heart rate varies greatly, but the abrupt change was small. Take the change trend of the HRI in the curve segment as an indicator, heart rate types were divided into 4 categories, continuous tension, relax gradually, relaxation-tension, and tension-relaxation. The 4 modes have a significant relationship with the difference of curve entrance environment. Compared with the modes shown in general curves, they focus on the modes with greater volatility, while the general curves focus on a more single growth trend.

Basalt fiber-reinforced polymer bars are lightweight composite materials with high strength, low density, and excellent corrosion resistance. The anchor system made from basalt fiber-reinforced polymer bars is worthy of being developed and expected to be used in rock anchoring projects. In this work, four different basalt fiber-reinforced polymer anchor systems were designed, the influences of different design parameters on the ultimate bearing capacity of the anchor system were investigated through tension tests, and the failure modes of different anchor systems were elucidated. The test results indicated that failure modes, such as the transverse fracture of these bars and debonding of the bonding medium, were widely present in the wedge-modified anchor system and the steel-pipe-protected anchor system. These two anchor systems performed poorly with the wedge anchorage, whereas the basalt fiber-reinforced polymer bars protected by seamless steel pipes burst under the tension imposed by a universal testing machine. The threaded steel-pipe-bonded anchor system and the steel strand–basalt fiber-reinforced polymer bar composite anchor system had maximum anchorage efficiency coefficients of 97.7% and 98.5%, respectively. The bars in the corresponding test groups all exhibited burst failure, indicating that these two anchoring structures achieved effective anchorage of the basalt fiber-reinforced polymer bars.

Shear friction is an important deformation process in tectonically deformed coals (TDCs) and is closely related to the dynamic metamorphism of coal. In the current study, we perform a molecular dynamics (MD) simulation of the shear friction process on primary structure coal. The simulation results show that coal friction is a process of energy transformation. The mechanical energy of shear friction work can lead to temperature increases and chain motion. Chain diffusion and reorientation are the two main chain motion modes during friction. Chain diffusion behavior is regular in the initial friction stage and becomes irregular in the later friction stage. The orientation change is different for various fused aromatic chains. The orientation changes of pentacenes and naphthacenes are more significant than those of the other fused aromatic chains, indicating that fused aromatic chains with a higher aspect ratio are preferentially reorientated by shear friction. It is also demonstrated that the C-O and C-N bonds in coal are more easily disassociated by shear friction. The research results directly confirm the molecular evolution during coal friction caused by shear stress.

The apertures of cleats and micro-fractures in coal play an important role in the permeability of the coal bed. In this study, optical microscopy and scanning electron microscopy were used to investigate the morphology of cleats and micro-fractures and their apertures, distribution of minerals, and matrix/fracture interactions. The neighboring mineralized and unmineralized cleats suggest the possibility of multi-stage evolutionary processes of cleat formation during the coalification process. The micro-fracture distribution of coals is closely related to their components, including organic macerals and inorganic minerals. Micro-fractures are prone to developing at the junction surface of organic macerals or the surface of organic and inorganic minerals. A mineral-genetic micro-fracture can be classified as an intra-crystal micro-fracture, an extra-crystal micro-scale fracture, or a grain-edge micro-scale fracture. Compared with the low- and middle-ranking coals, cleat and micro-scale fractures in high-ranking coal are usually filled with carbonate minerals and clay minerals. Statistical analysis reveals that the aperture distribution of cleat and micro-fracture in coal shows a log-normal distribution. The aperture of cleat and micro-fracture shows a decreasing trend with increase in coal rank. For low-ranking coal, cleats contribute more to the permeability than micro-fractures. However, for the middle- and high-ranking coals, the contribution of cleats and micro-fractures to the coal reservoir permeability will be close. As the rank of coal increases, the degree of cleat contribution to reservoir permeability decreases, while the degree of micro-fracture contributing to the reservoir permeability increases. Possible reasons for the extremely low reservoir permeability in China may be the following: 1) subsurface cleats and micro-fractures close their apertures significantly due to the in situ geo-stress or 2) cleats and micro-fractures have better permeability in the geological history, which makes the precipitation of minerals decrease the coal reservoir permeability. Therefore, the acid solvent (e.g., HAc, HCl, and HF) added to the drilling or hydraulic fracturing fluid or the geo-stress relief technologies may be an effective way of enlarging the cleat or micro-fracture aperture and enhance the reservoir permeability for coalbed methane production.

The interval changes in yellow light signals significantly impact driving behaviors that affect traffic safety. This study aims to compare the applicability of different interval changes in yellow light signals from the perspectives of drivers. Data acquisition was conducted in a naturalistic driving experiment with equipment including V-BOX, Ergo LAB, and I-View HED4 to acquire vehicle running index data, driver physiological and psychological index data, and eye movement index data, respectively. Twenty experienced drivers were recruited as subjects and were categorized as safe, average, or dangerous drivers. Based on the data obtained, driving behaviors for different interval changes in yellow light signals were studied using an Atlas. Observations of the driving behavior Atlas reveal that there are notable differences in driving behaviors for different interval changes in yellow light signals. Also, it was found that dangerous drivers are more likely to be affected by the interval changes in yellow light signals. It is necessary to choose reasonable signal transition modes to improve the safety of intersections based on actual road conditions and types of drivers. The results can guide traffic management departments when choosing a reasonable transition method for yellow light signals and help formulate customized training programs for different types of drivers. In particular, the results help in providing training on driving speed and deceleration control for dangerous drivers, which will help improve traffic safety.

Coalbed methane (CBM) resources cannot be efficiently explored and exploited without a robust understanding of the permeability of fracture-size heterogeneities in coal. In this study, two sister coal samples were imparted with pre-developed cleat and connected fractures, and the permeability of the coal samples was measured under different conditions of controlled confining and gas pressures. Furthermore, the implications of the results for CBM exploration and exploitation were discussed. The permeability of coal with cleat development ranged from 0.001–0.01 mD, indicating ultra-low permeability coal. The gas migration in this coal changed from a linear flow to a non-linear flow, with the increase in gas pressure (>1 MPa). Thus, the permeability of the coal initially increased and then decreased. However, the Klinkenberg effect does not exist in this ultralow-permeability coal. For the coal sample with connected fracture, permeability ranged from 0.1–10 mD, which is larger by hundred orders of magnitude than that of the sample with cleat. For this coal, with a decrease in gas pressure (

Prestressed anchor cable is widely used in geotechnical engineering to control the displacement or landslide of an unstable slope. However, the traditional cable anchor is made of steel material, which is easy to get rust in a corrosive environment. Basalt fiber-reinforced plastics (BFRP) are a kind of emerging compound material, with a good performance of high strength, low weight, and anticorrosion. Herein, an innovative large-tonnage pressure-type prestressed anchor is made with BFRP. This large-tonnage BFRP anchor cable has seven bunch structures of the “BFRP-connector-strand.” In each bunch of the “BFRP-connector-strand,” three BFRP tendons and one steel strand are connected inside a steel sleeve connector using the epoxy resin adhesive. The ultimate load-bearing capacity of this BFRP cable anchor can reach 202.38 tonnages. At the ultimate tensioning force condition, the strain of BFRP tendons for this large-tonnage BFRP anchor cable ranges from 1.51% to 1.76%. In the tensioning operation, there is a linear growth relationship between the tensioning force and the strain for this BFRP cable anchor. Once the tensioning force reaches the ultimate strength of this BFRP anchor cable, this cable will present system failure. This situation primarily results from the failure of the “BFRP-connector-strand.” The failure modes of this BFRP anchor cable can be classified into three types: the steel strand rupture, the steel connector rupture, and the BFRP tendon rupture. During the tensioning operation, due to the length difference of the BFRP tendons, this large-tonnage BFRP cable anchor presents an end-off-axis effect. It makes the load bearing of the BFRP tendons 5.00~6.60 times larger than that of the no end-off-axis effect. Nevertheless, due to the plastic deformation of the end steel anchor sleeve, the influence of the end-off-axis effect decreases with the increase of applied tensioning force. The load-bearing capacity of this large-tonnage BFRP cable anchor reaches 87.70~91.50% of its theoretical value.

The mechanical equation on the mechanical characteristics of rock bolt in rock mass with bedding separation is established, based on the bond slip relationship of anchoring interface by the load transfer method. The validity of the numerical simulation is verified by the analytical solution of mechanical equation, when the bond slip relationship is linear. Further, the nonlinear bond slip relationship of anchoring interface is input into Flac3D by FISH. The mechanical characteristics of rock bolt are studied with the single and multiple bedding separation by numerical simulation. The results show that the axial force and the interfacial shear stress distribution curves on both sides are symmetrically distributed with the single bedding separation in rock mass, when the bedding separation is located in the center of the anchoring segment. When the bedding separation positions are not located in the center of the anchoring segment, the bedding separation value at different positions versus the axial force curves shows a single peak distribution. The axial force of rock bolt is mainly controlled by the side with the shorter anchoring length. Compared with the single bedding separation in rock mass, the additional stress of rock bolt occurred by the multiple bedding separation will superimpose each other. This paper leads to a better understanding for the load transfer mechanism for grouted rock bolt systems in rock mass with bedding separation and provides a reference for scientific support design and evaluation method.

Vortex-induced vibration (VIV) is one of the most common dynamic mechanisms that cause damage to marine risers. Hamilton’s variational principle is used to establish a vortex-induced vibration (VIV) model of a flexible riser in which the wake oscillator model is used to simulate cross-flow (CF) and inline flow (IL) vortex-induced forces and their coupling, taking into account the effect of the top tension and internal flow in the riser. The VIV model is solved by combining the Newmark-β and Runge–Kutta methods and verified with experimental data from the literature. Combining Option 1 and Option 2 failure assessment diagrams (FADs) in the BS7910 standard, a fracture failure assessment model for a marine riser with circumferential semielliptical outside surface cracks is established. Using the VIV model and FAD failure assessment chart, the effects of riser length, inside/outside flows, and top tension on the VIV response and safety assessment of marine risers with outside surface cracks are investigated. It is shown that increasing the top tension can inhibit the lateral displacement amplitude and bending stress in a riser, but excessive top tension can increase the axial stress in the riser, which counteracts the decrease in the bending stress, so that the effect of top tension on crack safety is not significant. The increasing outside flow velocity significantly increases the lateral vibration amplitude and bending stress in the riser and reduces the crack safety. When other parameters remain unchanged, increasing riser length has no significant effect on the vibration amplitude of the lower part of the riser.

This study aims to investigate the impact of the urban undersea tunnel longitudinal slope on the visual characteristics of drivers. 20 drivers were enrolled to conduct the real vehicle test of the urban undersea tunnel. First, the data of average fixation time and visual lobe were collected by an eye tracker. The differential significance was tested using the one-way repeated measures analysis of variance (ANOVA). Then, the difference between the up-and-down slope (direction) factor and the longitudinal slope (percent) factor on the two indexes were analyzed using the two-way repeated measures ANOVA. Second, by constructing a Lorentz model, the impact of the longitudinal slope on the average fixation time and the visual lobe were analyzed. Besides, a three-dimensional model of the longitudinal slope, average fixation time, and visual lobe was quantified. The results showed that the average fixation time and visual lobe under different longitudinal slopes markedly differed when driving on the uphill and downhill sections. The average fixation time and visual lobe under two factors were markedly different. Moreover, with an increase in the longitudinal slope, the average fixation time exhibited a trend of increasing first then decreasing; the visual lobe exhibited a trend of decreasing first and then increasing. The average fixation time reached the minimum and maximum value when the slope was 2.15% and 4.0%, whereas the visual lobe reached the maximum and minimum value when the slope was 2.88% and 4.0%. Overall, the longitudinal slope exerted a great impact on the visual load of the driver.

Coalbed methane is now large-scalely explorated and exploitated in the world. The Changzhi coalbed methane block, south-central Qinshui Basin, is a new resource target zone for coalbed methane exploration and exploitation in China. However, the gas content distribution of this block and its influential factors have not yet studied. Based on the recent coalbed methane exploration and exploitation activities, the gas content distribution of coal reservoir in this block was studied. The results show that the gas content hold by the coal reservoir is 7.0 − 21.7 m 3 /t, which was determined by a combining control effect from geologic structure and hydrogeology. The Changzhi coalbed methane block has experienced multiple-stages geologic structure evolution, especially a tectonic-thermal event during the middle Yanshanian Orogeny improved the coal to the current R o ,max 1.9 − 2.7% and meanwhile the coalbed methane was greatly generated. Subsequently, the widespreadly developed normal fault structures during the Himalayan Orogeny accelerated the coalbed methane escape through the “gas escape windows”, particularly where the location within the distance of about 1300 m to the “gas escape window” the gas content decreases significantly. Moreover, due to the action of the later Himalayan Orogeny, the slope areas of most Yanshanian fold structures were structurally cross-cut by the Himalayan normal faults, and thus an “open” syncline folds were formed. The coal reservoir was depressurized surrounding this “open” syncline structure and consequently the hydrodynamic losing effect has resulted in a comparatively lower gas content therein. By the control of geologic structure and hydrogeology, this block can be generally, compartmentalized into three hydrodynamic systems including the western groundwater stagnation region, the middle runoff region, and the north-eastern recharge region, where the hydrodynamic sealing effect at the groundwater stagnation region has made a comparatively higher gas content for the coal reservoir, but the hydrodynamic losing effect at the recharge region and runoff region has made a comparatively lower gas content of the coal reservoir.

Speed illusion is the leading contributing factor to traffic accidents in highway tunnels. This study aimed to estimate the influence of visual information at different scales and frequencies on drivers’ visual perception and driving safety in highway tunnels. The speed perception of drivers was measured using the stimulus of subjectively equivalent speeds as an index. Thirty drivers were recruited to conduct a psychophysical experiment on speed perception using a driving simulator. The large-, medium- and small-scale visual information in a frequency range of 0.1–32 Hz were used in the experimental scene to generate scenes for comparison. The results show that high-frequency visual information (2–32 Hz) might lead to driver overestimation of vehicle speed in tunnels, while medium-frequency (0.4–1 Hz) and low-frequency (0.1–0.2 Hz) visual information contribute to speed underestimation. The medium-scale information had the largest speed overestimation effect, followed by large- and small-scale information (significant differences of 2–8 Hz). Medium-scale visual information below 8 Hz had the lowest degree of dispersion of speed perception. Therefore, the use of integrated high-frequency, medium-scale visual information and medium-frequency, large- and small-scale visual information is suggested to reduce the speed illusion of drivers and ensure driving safety.

As typical weak visual reference systems, highway tunnels have low illumination, monotonous environment and few references, which may cause severe visual illusion and reduce drivers’ speed perception ability. Thus, drivers tend to underestimate their driving speed, which may induce speeding behaviours that result in rear-end collisions. The cost-effective pavement markings installed on both sides of the lane or shoulder may make drivers overestimate their speed. This perception can help ensure safe driving and regulate driving behaviour effectively. This study analyses the effects of sidewall markings in typical low luminance highway tunnels, specifically observing how their angles and lengths affect the driver’s speed perception. A three-dimensional model of highway tunnels was built in a driving simulator. Psychophysical tests of speed perception were carried out by the method of limits. The simulation tests studied the Stimulus of Subjectively Equal Speed (SSES) and reaction time in relation to sidewall markings with different angles. Furthermore, based on the optimal angle, the effects of sidewall marking with different lengths on speed perception were also analysed. The test results reveal that the angle and length of sidewall markings have a significant impact on the driver’s SSES and reaction time. Moreover, the level of speed overestimation decreases with the increase of angle or length of sidewall marking. As the angle of sidewall marking gradually increases, the maximum reaction time first increases and then decreases. Within the angle of sidewall marking of 15°, the subjects have the highest speed overestimation and an easy speed judgment. This may due to Zöllner illusion, the driver’s perception of lane width shrinks may induce deceleration behaviour.

Utilizing the EMR-8B eye-tracker system, the pupil changes of eight drivers were monitored when they drove through 26 typical highway tunnels. Based on the test results, the driver’s pupil areas and pupil illuminance were found to be in a power function relationship at tunnel entrances. Furthermore, a quantitative relationship between the pupil area and its critical velocity was established, and the ratio of pupil area’s velocity in relation to its critical velocity was used to evaluate the lighting transitions and to establish the ideal curve of pupil illuminance at tunnel entrances. The results demonstrated that the relationship between the pupil illuminance of the tunnel entrance and the driver’s pupil areas conforms to the Stevens law found in experimental psychology; severe pupil illuminance transition within the range of 10 metres of the existing highway tunnel entrances, which results in great visual load, is in urgent need of improvement.

Abstract Flexible sensors have been widely studied for use in motion monitoring, human‒machine interactions (HMIs), personalized medicine, and soft intelligent robots. However, their practical application is limited by their low output performance, narrow measuring range, and unidirectional force detection. Here, to achieve flexibility and high performance simultaneously, we developed a flexible wide-range multidimensional force sensor (FWMFS) similar to bones embedded in muscle structures. The adjustable magnetic field endows the FWMFS with multidimensional perception for detecting forces in different directions. The multilayer stacked coils significantly improved the output from the μV to the mV level while ensuring FWMFS miniaturization. The optimized FWMFS exhibited a high voltage sensitivity of 0.227 mV/N (0.5–8.4 N) and 0.047 mV/N (8.4–60 N) in response to normal forces ranging from 0.5 N to 60 N and could detect lateral forces ranging from 0.2–1.1 N and voltage sensitivities of 1.039 mV/N (0.2–0.5 N) and 0.194 mV/N (0.5–1.1 N). In terms of normal force measurements, the FWMFS can monitor finger pressure and sliding trajectories in response to finger taps, as well as measure plantar pressure for assessing human movement. The plantar pressure signals of five human movements collected by the FWMFS were analyzed using the k-nearest neighbors classification algorithm, which achieved a recognition accuracy of 92%. Additionally, an artificial intelligence biometric authentication system is being developed that classifies and recognizes user passwords. Based on the lateral force measurement ability of the FWMFS, the direction of ball movement can be distinguished, and communication systems such as Morse Code can be expanded. This research has significant potential in intelligent sensing and personalized spatial recognition.