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The existing long-distance transmission line perception mainly focuses on the measurement and analysis of electrical parameters. When the line is subject to wind vibration, icing or galloping, the changes of electrical parameters are not obvious and difficult to capture, resulting in poor performance of long-distance transmission line fault state perception. In this regard, the long-distance transmission line condition sensing based on distributed optical fiber sensing technology is studied. This method designs corresponding sensing methods for four working conditions: using the back Brillouin scattering sensor and phase sensitive Rayleigh scattering sensor in the optical fiber sensing technology to form a multi parameter distributed optical fiber sensing device, which is used to sense the surface temperature, vibration, strain and other data of the long-distance transmission line; By analyzing the linear relationship between fiber Brillouin frequency shift and Brillouin power and fiber strain and temperature, the sensing results of icing thickness of long-distance transmission lines are obtained; By calculating the amplitude and phase information of the detection signal, the sensing results of long-distance transmission line vibration are obtained; By calculating the time difference of polarization mutation signal at both ends of long-distance transmission line, combined with the propagation speed of optical signal and the length of long-distance transmission line, the perception result of lightning fault location of long-distance transmission line can be obtained. The experimental results show that this method can more accurately collect the real-time operation data of long-distance transmission lines, and can effectively perceive the galloping, wind vibration and lightning fault location of long-distance transmission lines. [ABSTRACT FROM AUTHOR]

The deep integration of communication and sensing technology in fiber-optic systems has been highly sought after in recent years, with the aim of rapid and cost-effective large-scale upgrading of existing communication cables in order to monitor ocean activities. As a proof-of-concept demonstration, a high-degree of compatibility was shown between forward-transmission distributed fiber-optic vibration sensing and an on–off keying (OOK)-based communication system. This type of deep integration allows distributed sensing to utilize the optical fiber communication cable, wavelength channel, optical signal and demodulation receiver. The addition of distributed sensing functionality does not have an impact on the communication performance, as sensing involves no hardware changes and does not occupy any bandwidth; instead, it non-intrusively analyzes inherent vibration-induced noise in the data transmitted. Likewise, the transmission of communication data does not affect the sensing performance. For data transmission, 150 Mb/s was demonstrated with a BER of 2.8 × 10−7 and a QdB of 14.1. For vibration sensing, the forward-transmission method offers distance, time, frequency, intensity and phase-resolved monitoring. The limit of detection (LoD) is 8.3 pε/Hz1/2 at 1 kHz. The single-span sensing distance is 101.3 km (no optical amplification), with a spatial resolution of 0.08 m, and positioning accuracy can be as low as 10.1 m. No data averaging was performed during signal processing. The vibration frequency range tested is 10–1000 Hz. [ABSTRACT FROM AUTHOR]

Palmprint has a high application prospect due to the stability, uniqueness, difficulty of reproduction, easy acquisition and high user acceptance of its own texture characteristics. However, palmprint images acquired at long distances and in low light conditions lose a amount of significant palmprint texture features, which in turn will affect the accuracy of palmprint recognition. Combining traditional methods with deep learning methods, this paper proposes a low-illumination palmprint image enhancement method based on wavelet transform and GUNet (insertion of Integrated Attention Gate at the UNet jump connection). Firstly, the input image is decomposed by wavelet transformation to obtain the decomposition result of the original image, that is the high-frequency image and the low-frequency image. Secondly, the high-frequency image is enhanced by the GUNet neural network to enhance the palmprint texture, and low-frequency images use weighted averaging to smooth low-frequency information other than palm texture information. After that, the palmprint image with a clear palmprint texture is obtained by the wavelet inverse transformation. Numerous experiments are carried out on palmprint databases such as Idiap, CASIA, IITD and a laboratory self-collection. Experimental results show that the proposed approach has higher Peak Signal-to-Noise Ratio (PSNR), Structural Similarity (SSIM) and Visual Information Fidelity (VIF) indicators than some existing methods, which suggest palmprint image with low-illumination can be significantly enhanced. [ABSTRACT FROM AUTHOR]

Air handling units (AHUs) with long distance flexible film air ducts are commonly adopted in modern large-scale greenhouses for temperature controlling. To study the performance of this type of AHU, theoretical analysis and numerical simulation methods were used to discover its air supply characteristics, and a full-scale experiment was carried out to verify the correctness of the calculation model. The calculation showed that the static pressure of different cross-sections in the thin film air duct sharply decreased to 0 at the small-hole opening, where the airflow velocity increased significantly. However, this influence only exists locally and had little effect on the pressure and gas velocity fields inside the wind duct. The velocity and velocity distribution of the gas flowing out from different openings on the same section of the wind duct are basically the same. Taking the wind speed of 2.45 m/s at the inlet end of the wind duct as an example, the maximum velocity of the airflow at the opening position of the wind duct wall at 60.06 m is 5.64 m/s, located at the center of the opening and flowing outward perpendicular to the opening plane. The velocity distribution is that the center has the highest velocity, and the closer to the edge of the hole, the lower the velocity. The volum of the airflow flowing out through the openings on the wall of the wind duct along the length direction shows that the air supply remains basically constant under different inlet wind speed conditions, and the uniformity coefficient is greater than 0.92. This indicates that this type of AHU can evenly distribute airflow along the length direction, and can evenly distribute heat or cold in the large space of the greenhouse, thus providing a guarantee for maintaining a uniform temperature field in modern large greenhouses. [ABSTRACT FROM AUTHOR]

In the face of increasing demands for tasks such as mountain rescue, geological exploration, and military operations in complex wilderness environments, planning an efficient walking route is crucial. To address the inefficiency of traditional two-dimensional path planning, this paper proposes a two-stage path planning algorithm. First, an improved Probabilistic Roadmap (PRM) algorithm is used to quickly and roughly determine the initial path. Then, the morphological dilation is applied to process the grid points of the initial path, retaining the surrounding area of the initial path for a precise positioning of the search range. Finally, the idea of the A∗ algorithm is applied to achieve precise path planning in the refined search range. During the process of constructing the topology map, we utilized parallelization acceleration strategies to expedite the graph construction. In order to verify the effectiveness of the algorithm, we used terrain data to construct a wilderness environment model, and tests were conducted on off-road path planning tasks with different terrains and distances. The experimental results show a substantial enhancement in the computational efficiency of the proposed algorithm relative to the conventional A∗ algorithm by 30 to 60 times. [ABSTRACT FROM AUTHOR]

AbstractOrienteering is a popular outdoor sport that combines navigation, endurance, and decision-making skills. Understanding the factors that influence competitors’ results in orienteering races is of great interest to athletes, coaches, and selectors. Therefore, this study aims to investigate the factors influencing competitors’ results in different classes in the Long distance race of the 2022 China National Orienteering Championships. Trajectory distances [Formula: see text] are measured, and the speed of straight-line segments [Formula: see text] of each competitor’s trace [Formula: see text] is sampled by using GPS trajectory data. First, elite class results exhibit weak linear correlations ([Formula: see text] and [Formula: see text]) with total trajectory distances, whereas non-elite class results show significant linear correlations ([Formula: see text] and [Formula: see text]). Second, the M21E and W21E class results are significantly correlated ([Formula: see text] and [Formula: see text]) with median speed, as are non-elite men class results ([Formula: see text] and [Formula: see text]). Non-elite women class results display a weaker linear correlation ([Formula: see text] and [Formula: see text]). Finally, the study found that the M21E class had a significantly higher running speed than the M21A and M35A, while the disparity between W21E and W21A/W30A classes was smaller. The results indicate that elite competitors with better physical ability tend to have better results. Non-elite male competitors with better physical ability and better route choice ability tend to have better results. Non-elite female competitors who make more rational route choices tend to have better results. Non-elite male competitors need to improve their physical ability further to become elite competitors. In contrast, the distinction between non-elite and elite female competitors mainly lies in their technical abilities.

Organ preservation in heart transplantation is key to preventing primary graft dysfunction, the most common cause of early graft loss. Historically, the standard of care was preservation on ice, with no monitoring ability and problems with even temperature distribution. Recently, the SherpaPak, an Food & Drug Administration-approved transport device, has emerged as a solution to these 2 issues, allowing for even temperature distribution, no organ contact with ice, and continuous monitoring during transport. This method of transport falls under static cold preservation, but may allow for longer ischemic times beyond the recommended 4-hour limit. Here, we report a case of heart transplantation using the SherpaPak transport device for a distance of almost 3000 miles and total ischemic time over 7 hours—the longest yet reported for a donor heart transported using the SherpaPak system. The patient had excellent functional outcomes with no evidence of primary graft dysfunction. This case suggests that, with careful donor and recipient selection, SherpaPak may potentially be used for longer distances and ischemic times than initially recommended, as a safe and cheaper alternative to ex-vivo perfusion devices.

Taking No.12302 roadway of Wangjialing Mine as the research background, the advance support technology was researched by means of field investigation, theoretical analysis and engineering practice. The main problems that should be solved of the advance support are analyzed by field investigation, and the advance support ideas of long-distance support and non-repeted support was proposed. The distance from the peak of the advance concentrated stress to the working face was 8.22 m, and the length of the area affected by the advance mining was 37.09 m through theoretical analysis. Combined with the actual monitoring results of the previous site, the length of the advance support was determined to be no less than 40 m. Considering the support effect of the bolt (cable) support system, the advance support strength was determined to be no less than 267.38 kPa. This way, the long-distance advance support concepts of “pre-active support, one-time bearing, cooperative operatation, and overall support” was proposed, the type of ZLQ3200/18/37 advance support and transportation equipment was developed, the main technical parameters of the support device were introduced, and the long-distance advance support scheme was determined combined with the actual mining geological conditions. Practice shows that the application of long-distance and non-repeated advance support technology is effective, the entry surrounding rock has been well maintained, which can meet the requirements of safety advance support for mining entry.

The deep integration of communication and sensing technology in fiber-optic systems has been highly sought after in recent years, with the aim of rapid and cost-effective large-scale upgrading of existing communication cables in order to monitor ocean activities. As a proof-of-concept demonstration, a high-degree of compatibility was shown between forward-transmission distributed fiber-optic vibration sensing and an on–off keying (OOK)-based communication system. This type of deep integration allows distributed sensing to utilize the optical fiber communication cable, wavelength channel, optical signal and demodulation receiver. The addition of distributed sensing functionality does not have an impact on the communication performance, as sensing involves no hardware changes and does not occupy any bandwidth; instead, it non-intrusively analyzes inherent vibration-induced noise in the data transmitted. Likewise, the transmission of communication data does not affect the sensing performance. For data transmission, 150 Mb/s was demonstrated with a BER of 2.8 × 10−7 and a QdB of 14.1. For vibration sensing, the forward-transmission method offers distance, time, frequency, intensity and phase-resolved monitoring. The limit of detection (LoD) is 8.3 pε/Hz1/2 at 1 kHz. The single-span sensing distance is 101.3 km (no optical amplification), with a spatial resolution of 0.08 m, and positioning accuracy can be as low as 10.1 m. No data averaging was performed during signal processing. The vibration frequency range tested is 10–1000 Hz.

In the face of increasing demands for tasks such as mountain rescue, geological exploration, and military operations in complex wilderness environments, planning an efficient walking route is crucial. To address the inefficiency of traditional two-dimensional path planning, this paper proposes a two-stage path planning algorithm. First, an improved Probabilistic Roadmap (PRM) algorithm is used to quickly and roughly determine the initial path. Then, the morphological dilation is applied to process the grid points of the initial path, retaining the surrounding area of the initial path for a precise positioning of the search range. Finally, the idea of the A∗ algorithm is applied to achieve precise path planning in the refined search range. During the process of constructing the topology map, we utilized parallelization acceleration strategies to expedite the graph construction. In order to verify the effectiveness of the algorithm, we used terrain data to construct a wilderness environment model, and tests were conducted on off-road path planning tasks with different terrains and distances. The experimental results show a substantial enhancement in the computational efficiency of the proposed algorithm relative to the conventional A∗ algorithm by 30 to 60 times.

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To address the delamination and water leakage caused by the fracture of insulated chilled water pipeline (ICWP) in the process of long-distance drilling through deep strata, a new insulated cold transmission pipe with a composite structure was designed based on the actual project. The mechanical and deformation characteristics of the mortar materials of the different filling layers were investigated using uniaxial compression and Brazilian split tests. The distribution law of the maximum principal strain field on the surface during the test process was obtained by applying the digital image correlation method. Based on the experimental results, the finite-difference model was established and FLAC3D was used to analyze the stability of the long-distance composite structure ICWP under different stress conditions. The numerical results show that when the ground stress exceeds 12 MPa, the plastic damage occurs in the inner and outer filling layers of the ICWP. When the ground stress reaches 17.5 MPa, there is a small plastic zone in the cold transmission pipe, but the composite structure ICWP does not affect the regular operation of the pipe. Based on that, the mapping relationship for the plastic damage rate of the inner and outer filling mortar of the ICWP to the ground stress and the parameters of the insulation pipe was constructed to provide a theoretical basis for improving the deformation damage resistance characteristics of the composite structure ICWP. [ABSTRACT FROM AUTHOR]

To make travelling with electric vehicles (EVs) over long distances as convenient as travelling with traditional vehicles, charging stations along motorways are necessary. Furthermore, waiting times for free charging points must be short to enable a fast onward journey, and this also on days with heavy traffic volumes. To determine the required number of charging stations in more detail, a model was created that simulates the process of arriving and leaving cars at a charging park based on real traffic data. For the traffic data, a location and date in the Munich region were chosen that represent a peak demand and thus a “worst case” scenario. The ability to cover such scenarios as well seems to be important because otherwise severe congestion with long waiting times would appear on days with heavy traffic, which would make the use of EVs very unattractive. It turned out that 150 to 600 charging stations – depending on the considered scenario – would be necessary to charge proportions of 10% to 20% of all passing cars.

Forensic engineering methods might be applied in detection and identification characterisation of events according to complexity of their appearance in real environment as it covers different aspects (data, materials, chemistry, monitoring systems, technology) needed to find out the cause and predict effects. The long-distance air pollutant transport represents one challenging event for the analysis over years; specific phenomena are Saharan air masses that can transport high amounts of mineral dust particles and biological material. The dynamism of the systems in real environment, inevitably, includes time frame and spatial referencing, on location of event. However, this is directly related to providing findings and opinions when appealing to a forensic examination of an event. An example of long-distance transport of air pollutants with references to related processes in the atmosphere including time frame and spatial references is presented in the paper with discussion that is aligned with the goals of forensic engineering.

The traditional triangle elevation method for ranging is affected by the error by vertical refraction of the atmosphere, distance measuring error and the error in measurement of the heights of the instrument and the targets, as a result, it is difficult to control the measurement accuracy and the working efficiency is low. To overcome these, this paper proposes a triangular elevation leveling method based on high and low prism method, that is, two high -precision total stations with automatic alignment functions are used to perform multiple measurement returns opposite observation in multiple periods of time on the self-designed high and low prism set. It is found after the cross-river measurement of the main body of Yanji Changjiang River Bridge in Hubei Province that, the maximum error of the height difference between measurement returns was 10.00 mm, and the maximum error of loop closure was 1.30 mm, and after adjustment, the accidental error per kilometer is only ±0.71 mm, the mean square error of elevation at the weakest point is ±0.20 mm, and the mean square error of elevation in the weakest survey section is ±0.20 mm, which all meet the limit requirements of the second-class leveling measurement. It has been proved that this method can meet the second-class leveling requirements for long-distance cross-river leveling of less than3500 m, and improve the working efficiency by 50% compared with the traditional ranging triangle elevation method, worth wide promotion and application. [ABSTRACT FROM AUTHOR]

Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the development of underwater navigation and underwater communication, it remains difficult to obtain time delay measurements after propagating long distance. This paper proposes an improved high-accuracy time delay measuring method for long distance underwater channel propagation. First, by sending an encoded signal, the signal acquisition is carried out at the receiving end. Then, to improve signal to noise ratio (SNR), bandpass filtering is carried out on the receiving end. Next, considering the random changes in the underwater sound propagation channel, a strategy is proposed to select the optimal time window for cross-correlation. Then, new regulations are proposed to calculate the cross-correlation results. To verify the effectiveness of the algorithm, we compared it with other algorithms under low SNR conditions using Bellhop simulation data. Finally, the accurate time delay is obtained. With underwater experiments over different distances, the method proposed by the paper achieves high accuracy. The error is about 10−3 s. The proposed method makes a contribution to underwater navigation and communication. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Medicine & Science of Physical Activity & Sport / Revista Internacional de Medicina y Ciencias de la Actividad Física y del Deporte is the property of Revista Internacional de Medicina y Ciencias de la Actividad Fisica y del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Terahertz communications demonstrate advantages of wide bandwidth and low latency compared to the microwave counterparts but suffer from high propagation loss in the air. Little research focuses on long-distance (i.e., distance>1 km) terahertz propagation characteristics in the air, posing challenges on long-distance terahertz wireless applications. In this paper, the terahertz long-distance propagation characteristics are explored and studied with the help of the measurement system operating at 220 GHz. Based on the measurement systems, the outdoor experiments with a propagation distance of 2.5 km are conducted to obtain the terahertz propagation loss in the air. Additionally, a comparison between the measured propagation loss and the calculated one based on models issued by the international telecommunication union (ITU) shows an intrinsic loss gap between these two results, which is found and explained for the first time in the above-100 GHz long-distance communication applications. With the analysis of the collected data, a gap-compensation method is proposed to obtain a more accurate prediction for the propagation loss in the air. With the help of the implemented systems and corresponding measurements, we could give insight into the terahertz propagation and pave the way for future terahertz long-distance applications. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The transportation detection of long-distance small objects has low accuracy. In this work, we propose DMF, which is based on disparity depths. We map different disparity regions to 2D candidate regions according to the distance to solve the small-object detection problem. This method clusters disparity maps of different depths. The projected image is extracted with image features in the mapping region. On the one hand, it uses a multicluster method to unsample 2D mapping regions. On the other hand, the feature fusion of different scales is performed on each cluster region. The experimental results on two datasets show that DMF can improve the detection accuracy of small objects. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Trauma & Emergency Surgery / Ulusal Travma ve Acil Cerrahi Dergisi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AIM: The present study was undertaken to examine the effect of long-distance load marching on the physiological responses, walking efficiency, and mobility of soldiers at sandy desert environment. METHODS: A total of nine physically fit soldiers (age, 30.00 [SE 0.9] years; height, 175.56 [SE 1.18] cm; and weight, 77.83 [SE 1.37] kg) volunteered for long-distance (6 km) load marching by self-selected speed when carrying 22 kg (28.27% of body weight [BW]) load and no load (NL). Heart rate (HR), respiratory frequency (RF), and core body temperature (CBT) were recorded. Relative workload (RWL) and Physiological Cost Index (PCI) were calculated to assess the work intensity and mobility. RESULTS: It was observed that HR (P = 0.01), RWL (P = 0.01), and PCI (P = 0.01) were significantly increased by 23.79, 39.71, and 77.73%, respectively, and mobility was significantly reduced (P = 0.01) by 18.56% during marching with 22 kg load as compared to NL. CONCLUSION: It may be that marching without external load at speed of 4.85 ± 0.54 km/h should not be continued for more than 2 h, whereas marching with load of 28.27% of BW at speed of 3.95 ± 0.55 km/h should be restricted to maximum 30 min. This combination of load, speed, and duration provides information about soldiers' routine load carriage tasks, which may help in optimizing the load carriage task to reduce the chances of cumulative carriage-related injuries and, therefore, may contribute to improved soldiers' operational readiness and mobility.

Crosswell electromagnetic (EM) methods are widely used in subsurface geophysical prospecting because they can achieve more effective long-distance detection than single-well methods. However, a large-diameter borehole is required to increase the magnetic moment of the magnetic dipole source. For the long-distance detection of copper ores, which is usually performed in slim holes, we present a borehole-surface current-injection-based crosswell EM logging method. Considering the cost of deploying casing, we inject a low-frequency ac directly into the ground, and converging current is formed around low-resistance anomalies in the formation. Then, the distribution of the anomalies can be inferred by detecting the low-frequency alternating magnetic field of the converging current in the receiver well. Moreover, to further improve the detection performance, we design a placement scheme for the grounding electrode for multianomaly crosswell detection based on the Gauss–Newton inversion algorithm, where the EM responses for different grounding electrode locations are analyzed. Field experiments are conducted using two slim open holes spaced approximately 1000 m apart for the detection of two copper ores. Through the processing and interpretation of measured EM signals, the conductivity imaging results of the crosswell EM method indicate that the measured distribution of anomalies is consistent with prior knowledge obtained from numerous single-well loggings, demonstrating the feasibility of the proposed application for long-distance crosswell EM logging in slim open holes.

To address the delamination and water leakage caused by the fracture of insulated chilled water pipeline (ICWP) in the process of long-distance drilling through deep strata, a new insulated cold transmission pipe with a composite structure was designed based on the actual project. The mechanical and deformation characteristics of the mortar materials of the different filling layers were investigated using uniaxial compression and Brazilian split tests. The distribution law of the maximum principal strain field on the surface during the test process was obtained by applying the digital image correlation method. Based on the experimental results, the finite-difference model was established and FLAC3D was used to analyze the stability of the long-distance composite structure ICWP under different stress conditions. The numerical results show that when the ground stress exceeds 12 MPa, the plastic damage occurs in the inner and outer filling layers of the ICWP. When the ground stress reaches 17.5 MPa, there is a small plastic zone in the cold transmission pipe, but the composite structure ICWP does not affect the regular operation of the pipe. Based on that, the mapping relationship for the plastic damage rate of the inner and outer filling mortar of the ICWP to the ground stress and the parameters of the insulation pipe was constructed to provide a theoretical basis for improving the deformation damage resistance characteristics of the composite structure ICWP.

Aiming to survey scenarios of offshore projects with difficult horizontal elevation transmission and long-distance, all-weather elevation monitoring operations, a long-distance, total station, trigonometric leveling based on dynamic compensation is proposed. The feasibility of this method was verified by an outdoor survey experiment, and the range of transverse coverage and accuracy reached by this method was quantitatively analyzed. The results indicate that this method shows a good correction effect on the survey results of test points under different environmental conditions, which proves that this method is feasible. The correction effect of this method is affected by the distance between the test point and the datum point; within the range of 60 m horizontally from the datum point, an assurance rate of about 90% can be achieved for the error range of 20 mm. Combining with the built-in ATR (Automatic Target Recognition) technology of the total station, this method can make the elevation survey result reach the accuracy of millimeter level under the range of about 1000 m, by obtaining multiple groups of data and then calculating the mean value. This paper provides a new method for the elevation transfer of sea-crossing bridges under long-distance conditions and harsh environmental conditions. [ABSTRACT FROM AUTHOR]

Solutions of geodetic problem is an important technical problem in geodesy. Based on the comprehensive analysis of the characteristics of Bessel's formula and Vincenty's formula, an improved algorithm is proposed. Firstly, arctangent formula is replaced by arccosine formula to calculate spherical surface angular distance. Secondly, Bessel's formula is used to replace Vincenty's formula in the singular region. Finally, the test formulas of geodetic line and azimuth are given. According to the test formula, four points are selected for the test, which are located in the equator, low latitude, middle latitude and high latitude. The geodesic length range of the test is 1000–18000 km and the azimuth range is 0 ∘ – 360 ∘ . The experimental results show that the improved algorithm can solve the problem of singularity and quadrant judgment well. The solution precision of geodetic line is better than 1 mm, and the precision of azimuth is less than 0.0001 second. [ABSTRACT FROM AUTHOR]

BackgroundEven if the beneficial cardiovascular effects of moderate exercise are recognized, effects of prolonged and intense exercise are still debated. This study aims to detect cardiovascular changes associated with long endurance running by assessing the relationship between echocardiographic parameters and cardiac biomarkers during long-distance trail running.MethodsWe performed a prospective observational study that included 20 participants who were all amateur runners (median age of 41 years old, still alive after a 7-year clinical follow-up) from 80-km trail running. All the participants underwent an echocardiographic examination and venous blood sampling before the race, at the intermediate refreshment checkpoints of the race (21st and 53rd km), and within 10 min after arrival.ResultsMitral E/A velocity ratio and mitral TDI e’ wave were significantly decreased at the 21st km to arrival (p < 0.05). Mitral S wave and global longitudinal strain (GLS) were significantly decreased from the 53rd km to arrival (p < 0.05 for 53rd and 80th km). As compared to baseline, T-troponin and NT-proBNP were significantly increased at the 21st km in all the participants, but T-troponin values were systematically increased above the significative threshold. Diastolic echocardiographic abnormalities were mainly observed among participants with highest NT-proBNP (> 77 ng.l–1) values at the 21st km. As compared to baseline, mitral e’ wave was significantly decreased (–35%) in participants with highest values of NT-proBNP. Similarly, GLS was also depressed among participants with highest troponin values at the 53rd km (p = 0.01 for 53rd km and p = 0.04 for arrival).ConclusionDuring the long-distance trail running, the early LV decrease in diastolic echocardiographic parameters is associated with increase in NT pro-BNP blood levels, and the decrease in LV systolic echocardiographic parameters later is associated with increase in T-troponin blood levels.

With the development of underwater navigation and underwater communication, it remains difficult to obtain time delay measurements after propagating long distance. This paper proposes an improved high-accuracy time delay measuring method for long distance underwater channel propagation. First, by sending an encoded signal, the signal acquisition is carried out at the receiving end. Then, to improve signal to noise ratio (SNR), bandpass filtering is carried out on the receiving end. Next, considering the random changes in the underwater sound propagation channel, a strategy is proposed to select the optimal time window for cross-correlation. Then, new regulations are proposed to calculate the cross-correlation results. To verify the effectiveness of the algorithm, we compared it with other algorithms under low SNR conditions using Bellhop simulation data. Finally, the accurate time delay is obtained. With underwater experiments over different distances, the method proposed by the paper achieves high accuracy. The error is about 10−3 s. The proposed method makes a contribution to underwater navigation and communication.

Loop heat pipes (LHPs) are attractive two-phase thermal control devices for satellites, electronics and many other applications. They are capable of transporting heat efficiently for long distances up to several meters at any orientation. This paper investigated the heat transfer characteristics of loop heat pipes with long distances and small diameter transport lines. Small stainless steel tubes of 2 mm and 3 mm in inner diameters were chosen as liquid lines and vapor lines of the LHPs. The local thermal resistances in the evaporator of the 6 m-LHP were researched and analyzed, which indicated that the thermal resistance between the aluminum block and the vapor in the vapor channel accounted for a major proportion of the total thermal resistance. The effect of heat sink temperatures on the performance of the 6 m-LHP were compared with 10°C, 15°C, 20°C and 25°C cooling water temperatures. Moreover, the thermal characteristics of LHPs with transport distances of 2 m and 16 m were also experimentally investigated. The 16 m-LHP could achieve a heat transfer capacity of 100 W and the 2 m-LHP could reach more than 339 W, on the premise of the evaporator temperature below 100°C. The thermal resistance of the 2 m-LHP could achieve 0.125°C/W. [ABSTRACT FROM AUTHOR]

Aiming at the problem of target track offset that easily occurs in multi-radar multi-target detection and tracking when the target distance is close, this paper proposes a new type of multi-radar multi-target particle filter tracking before detection algorithm(NM-PF-TBD). The algorithm uses a two-layer particle filter structure. When tracking a target in the target tracking layer, the sensor detection information is recalculated based on other target points in the previous cycle. Secondly, the particle weight is calculated based on the corrected sensor detection information, and then. Based on the distribution of particles with different weights in the particle swarm, it deletes harmful particles, supplements beneficial particles, and avoids the shift of the center of the tracking particle swarm after re-sampling, so as to ensure that the target point trace does not shift. Simulation results show that, compared with other algorithms, the algorithm proposed in this paper can accurately correlate target traces and improve target accuracy when observing multiple closer targets at a long distance.

Nowadays, high-speed railway (HSR) has become one of the main choices for passengers. As the number of passengers increases, their travel demands become diverse and the fluctuation range of passenger travel demands will also increase. In order to adapt to the change of passenger travel demands, the switching frequency of timetables needs to be increased. When switching the timetable, the train-set circulation plan also needs to be considered. In this paper, a scheduling approach for quickly solving the timetable and the train-set circulation plan in the transition time is proposed. A section sequence is constructed in the integer programming model, and the primary train-set circulation plan is obtained. Then a stop plan is obtained on the basis of passenger travel demands. To obtain the final train-set circulation plan and the timetable, a genetic algorithm (GA) is designed, and a method that can ensure that the timetable meets the safety operation requirements is proposed. The scheduling approach is tested on the Beijing-Shanghai HSR. The results show that by extending the transition time, the scheduling approach can switch the train-set position from the old state to new state, without additional consumption of resources, on the premise of meeting the travel demands of passengers. [ABSTRACT FROM AUTHOR]

The hypothesis that feed ingredients could serve as vehicles for the transport and transmission of viral pathogens was first validated under laboratory conditions. To bridge the gap from the laboratory to the field, this current project tested whether three significant viruses of swine could survive in feed ingredients during long‐distance commercial transport across the continental US. One‐metric tonne totes of soybean meal (organic and conventional) and complete feed were spiked with a 10 ml mixture of PRRSV 174, PEDV and SVA and transported for 23 days in a commercial semi‐trailer truck, crossing 29 states, and 10,183 km. Samples were tested for the presence of viral RNA by PCR, and for viable virus in soy‐based samples by swine bioassay and in complete feed samples by natural feeding. Viable PRRSV, PEDV and SVA were detected in both soy products and viable PEDV and SVA in complete feed. These results provide the first evidence that viral pathogens of pigs can survive in representative volumes of feed and feed ingredients during long‐distance commercial transport across the continental United States. [ABSTRACT FROM AUTHOR]

In order to realize the power line extraction of long distance linear airborne light detection and ranging (LiDAR), a power line extraction method of long-distance airborne LiDAR based on cloth simulation was proposed. On the basis of data preprocessing, the function between cloth and corresponding airborne LiDAR point cloud was analyzed by simulating the falling process of cloth. The position where cloth stayed after gravity faUing was determined as the power line point cloud with similar height, and then the straight line was fitted in the xOy plane. The distances from points to the fitting line were used to judge the number of power lines whether odd or even. And the power line point clouds were divided by the judgment of points on both sides of the line to achieve the extraction of a single power line. The experimental results show that the accuracy of the proposed method is 98.9%, with high degree of automation and not sensitive to the lack of local point cloud, which has good engineering application value for intelligent poweriine inspection and automatic analysis of transmission channel spatial structure. [ABSTRACT FROM AUTHOR]

The primary nutritional challenge facing endurance runners is meeting the nutrient requirements necessary to optimize the performance and recovery of prolonged training sessions. Supplement intake is a commonly used strategy by elite and recreational distance runners to meet nutritional recommendations. This study was conducted to investigate the patterns of supplement intake among different groups of distance runners and the potential association between supplement intake and sex, age, running and racing experiences. In a cross-sectional design, from a total of 317 runners participating in this survey, 119 distance runners were involved in the final sample after data clearance, assigned into three groups of 10-km runners (n = 24), half-marathoners (n = 44), and (ultra-)marathoners (n = 51). Personal characteristics, training and racing experiences, as well as patterns of supplement intake, including type, frequency, and dosage, were evaluated by questionnaire. Food Frequency Questionnaire was implemented to assess macronutrient intake. ANOVA and logistic regression were used for statistical analysis. While 50 % of total distance runners reported consuming supplements regularly, no differences between distance groups in consumption of carbohydrate/protein, mineral, or vitamin supplements were observed (p > 0.05). In addition, age, sex, running and racing experience showed no significant association with supplement intake (p > 0.05). Vitamin supplements had the highest intake rate in runners by 43 % compared to minerals (34 %) and carbohydrate/protein supplements (19 %). The present findings provide a window into the targeted approaches of long-distance runners as well as their coaches and sport nutrition specialists when applying and suggesting sustainable nutritional strategies for training and competition. Trial registration: ISRCTN73074080. Retrospectively registered 12th June 2015. [ABSTRACT FROM AUTHOR]

The primary nutritional challenge facing endurance runners is meeting the nutrient requirements necessary to optimize the performance and recovery of prolonged training sessions. Supplement intake is a commonly used strategy by elite and recreational distance runners to meet nutritional recommendations. This study was conducted to investigate the patterns of supplement intake among different groups of distance runners and the potential association between supplement intake and sex, age, running and racing experiences. In a cross-sectional design, from a total of 317 runners participating in this survey, 119 distance runners were involved in the final sample after data clearance, assigned into three groups of 10-km runners (n = 24), half-marathoners (n = 44), and (ultra-)marathoners (n = 51). Personal characteristics, training and racing experiences, as well as patterns of supplement intake, including type, frequency, and dosage, were evaluated by questionnaire. Food Frequency Questionnaire was implemented to assess macronutrient intake. ANOVA and logistic regression were used for statistical analysis. While 50 % of total distance runners reported consuming supplements regularly, no differences between distance groups in consumption of carbohydrate/protein, mineral, or vitamin supplements were observed (p > 0.05). In addition, age, sex, running and racing experience showed no significant association with supplement intake (p > 0.05). Vitamin supplements had the highest intake rate in runners by 43 % compared to minerals (34 %) and carbohydrate/protein supplements (19 %). The present findings provide a window into the targeted approaches of long-distance runners as well as their coaches and sport nutrition specialists when applying and suggesting sustainable nutritional strategies for training and competition. Trial registration: ISRCTN73074080. Retrospectively registered 12th June 2015. [ABSTRACT FROM AUTHOR]

At present, the virtual navigation aids mainly refers to the AIS virtual navigation mark. Because the signal coverage of the AIS base station is limited, it is only suitable for inland rivers and offshore waters. In view of the problem that the AIS virtual navigation aids is not suitable for deep sea and ocean setting use, the concept of virtual navigation aids based on VDE)SAT was proposed. The VDE-SAT module in VDES can communication with satellites without the distance limit of information transmission. The VDE-SAT module was used to broadcast virtual navigation aids. At the same time, the message format for long-distance virtual navigation aids information was designed and verified whether it is reasonable, which provides a reference for the realization of the long-distance virtual navigation aids. [ABSTRACT FROM AUTHOR]

Objective To assess the visual acuity of commercial long-distance drivers in Benin City, Nigeria. Patients and methods A descriptive cross-sectional study design was used, and data were collected for 315 commercial long-distance drivers and their vehicles from January to October, 2013. Respondents were recruited using systematic random sampling technique. The study instruments included structured interviewer-administered questionnaires. Data were analyzed using SPSS, version 20. Results The results showed that 114 (36.2%) drivers were within the age group of 31–40 years. Most of the respondents [272 (86.3%)] were married; almost all the respondents [311 (98.7%)] were males, whereas four (1.3%) were surprisingly females. More than half of the respondents [172 (54.6%)] had a secondary level of education, whereas 12 (3.8%) had no formal education. Less than a tenth [30 (9.5%)] were visually impaired, with two (0.6%) having severe visual impairment, whereas majority of respondents had normal visual acuity [285 (90.5%)]. There were statistically significant associations between the respondents’ level of education (P

BACKGROUND: The present study determines to understand the maternal health-care infrastructure in Meghalaya, a state of Northeast India. The state has large number of population of 2,964,007 (Census 2011), however, the state has only two public District Hospitals related to maternal health-care services – one in East Khasi Hills District and the other one in West Garo Hills District. Furthermore, according to the National Rural Health Mission (2015–2016), the maternal mortality ratio of Meghalaya is 211/100,000 live births which is higher than the national average. MATERIALS AND METHODS: A hospital-based mixed method study has carried out to identify the problems faced by the women during their maternity period and to assess the quality and availability of maternal care infrastructure in Meghalaya. To conduct the interview, the present study covered all 80 pregnant women who were admitted in the major two district maternal health-care hospitals of Meghalaya for maternity care (i.e., delivery and postdelivery period) during the period of hospital visit in October 2019. RESULTS: The study shows that majority of the admitted women came from different villages of different districts of Meghalaya as those remote areas have no adequate maternal health-care institutions nearby other than dispensary or subcenter. The study also revealed that women who came to get treatment in hospital during pregnancy had to face difficulties like to travel a long distance, use public transport, bad road conditions, and financial problems. CONCLUSION: To improve the health scenario of health-care system in the remote village areas, the Government should give more focus on infrastructure development in terms of availability of adequate facilities for handling any emergency cases of maternal care in remote areas of Meghalaya. [ABSTRACT FROM AUTHOR]

Hikers performing long distances (1000–5500 kms a year) were analyzed using quantitative and qualitative methods to evaluate their mental well-being and to find their motivation as well as to analyze the excessive physical activity. 112 hikers completed a questionnaire (M(age) = 40.28, SD = 8.77, 57.1% male) and 25 individuals were interviewed. Distance had association only with perceived health status. There were no differences between males and females, as well as between age groups and educational attainments regarding distance. 33.3% of hikers indicated symptoms of loneliness and 4.5% were involved excessively in hiking that was significantly regressed by distress. Hikers had mainly intrinsic motivations to complete long distances including overcoming new challenges, finding the physical boundaries, experiencing a state outside the comfort zone, belonging to a special group with similar interest and attracted by the beauty of nature. Overcoming all these embodied in a flow experience that took them further to perform the new long-distance trails.

In ultrasonic measuring distance technology, traditional signal processing algorithms are difficult to analyze signals with long distances and weak echoes, and it is also impossible to measure the distance of multiple obstacles at the same time. In order to solve this problem, an ultrasonic measurement distance method based on random forest is proposed in this paper. Firstly the time domain characteristics of the signal—the relative peak amplitude and frequency domain characteristics—the relative area of the spectrum are extracted to judge the number of obstacles in the detection area by random forest method, and then calculates distance of obstacles. After the experiment, the algorithm can effectively measure the distance of multiple obstacles within 10 meters, and the measurement error is within 3 cm, which satisfies the practical application and has high practical value and theoretical reference significance.

In order to explore the impact of long-distance overlapping mining and coal pillar remaining on the roof collapse and floor pressure relief effect in No.8 mine of Pingdingshan Coal Company Limited, the similar simulation experiment of mining along coal seam dip was carried out. The experimental results show that with group Ding or group Wu coal seam mining, the stress increasing or releasing effect of the floor under the goaf or isolated island coal pillar weakens with the increase of the buried depth. The pressure relief angles of the upper and lower sides are respectively 65° and 75°. Coal pillar pressurization zone affects the group Ji coal seam. The pressure relief angles of group Ding and group Wu coal seams overlapping mining of the upper and lower sides are respectively 75° and 65°. The pressure relief area and pressure boosting area affects the group Wu coal seam with stress increment range limited. The dynamic pressurization value and pressure relief value of group Wu coal seam are higher than the additional stress after mining. Mining of group Ding coal seam has little effect on pressure relief protection, but the coal pillar causes additional stress in the coal seam. With group Ding and group Wu coal seams overlapping mining, the staggered arrangement of coal pillar and goaf is beneficial to the mining of group Ji coal seam. [ABSTRACT FROM AUTHOR]

Nowadays, high-speed railway (HSR) has become one of the main choices for passengers. As the number of passengers increases, their travel demands become diverse and the fluctuation range of passenger travel demands will also increase. In order to adapt to the change of passenger travel demands, the switching frequency of timetables needs to be increased. When switching the timetable, the train-set circulation plan also needs to be considered. In this paper, a scheduling approach for quickly solving the timetable and the train-set circulation plan in the transition time is proposed. A section sequence is constructed in the integer programming model, and the primary train-set circulation plan is obtained. Then a stop plan is obtained on the basis of passenger travel demands. To obtain the final train-set circulation plan and the timetable, a genetic algorithm (GA) is designed, and a method that can ensure that the timetable meets the safety operation requirements is proposed. The scheduling approach is tested on the Beijing-Shanghai HSR. The results show that by extending the transition time, the scheduling approach can switch the train-set position from the old state to new state, without additional consumption of resources, on the premise of meeting the travel demands of passengers.