Total Track Length Research Articles

Wide FOV metalens for near-infrared capsule endoscopy: advancing compact medical imaging

Abstract This study presents the design, fabrication, and characterization of a wide field-of-view (FOV) metalens optimized for capsule endoscopy. The metalens achieved a 165° FOV with a high modulation transfer function (MTF) of 300 lines per millimeter (lp/mm) across the entire FOV, operating in the near-infrared (NIR) narrow-bandpass imaging at 940 nm. The performance of the metalens-based system is evaluated using two bandwidths, 12 nm and 32 nm, showing MTF values of 0.2 and 0.3 at 250 lp/mm, respectively. The metalens-based system maintains a compact form factor with a total track length of 1.4 mm and a diameter of 1.58 mm. Compared to a traditional 108° FOV endoscope, the nano-optic capsule endoscope demonstrated superior performance in terms of FOV, contrast, and resolution. This advancement represents a significant step toward enhancing diagnostic capabilities in medical imaging, offering improved performance in a more compact package compared to conventional optics.

Increasing the theoretical and practical capacity of the Eastern Operating Domain by means of advanced train separation systems

Aim. Currently, the mainline railway network does not fully meet the market’s needs in terms of capacity, which is why every day JSC RZD is forced to reject 2 to 4% of applications for the transportation of goods across routes passing through limited-capacity railway infrastructure facilities. Increasing the practical capacity of railway lines by building additional tracks at stations and on open lines is unacceptably long and requires massive capital investments. Methods. It is proposed to solve the above problem by increasing the utilization of railway infrastructure by reducing the succession times and station operation times in the traffic schedule by deploying moving block and virtual coupling. This approach allows reducing capital investments up to 32 times and the duration of project implementation up to 8 times with a comparable capacity increase. The paper details the functionality of train separation technology and its technical parameters. Conclusion. The train separation technology has been deployed and is in operation on the Far Eastern, Trans-Baikal, East Siberian, and Krasnoyarsk Railways, branches of JSC RZD, that are part of the Eastern Operating Domain of JSC RZD network. By the end of 2023, the total length of track covered by the train separation solution was 5,734 km. Conclusion. In 2023, the lines of the Eastern Operating Domain handled almost 36 thousand pairs of trains with reduced spacing. The train separation technology also allows improving the safety and the level of digitalisation of the transportation process.

From snow accumulation to snow depth distributions by quantifying meteoric ice fractions in the Weddell Sea

Abstract. Year-round snow cover is a characteristic of the entire Antarctic sea ice cover, which has significant implications for the energy and mass budgets of sea ice, e.g., by preventing surface melt in summer and enhancing sea ice growth through extensive snow ice formation. However, substantial observational gaps in the seasonal cycle of Antarctic sea ice and its snow cover limit the understanding of important processes in the ice-covered Southern Ocean. They also introduce large uncertainties in satellite remote sensing applications and climate studies. Here we present results from 10 years of autonomous snow observations from Snow Buoys in the Weddell Sea. To distinguish between actual snow depth and potential snow ice thickness within the accumulated snowpack, a one-dimensional thermodynamic sea ice model is applied along the drift trajectories of the buoys. The results show that potential snow ice formation, with an average maximum thickness of 35 cm, was detected along 41 % of the total track length of the analyzed Snow Buoy tracks, which corresponds to about one-quarter of the snow accumulation. In addition, we simulate the evolution of internal snow properties along the drift trajectories with the more complex SNOWPACK model, which results in superimposed ice thicknesses between 0 and 14 cm on top of the snow ice layer. These estimates will provide an important reference dataset for both snow depth and meteoric ice rates in the Southern Ocean.

The Optimal Span Length of the Overhead Catenary System for the Gemas-Johor Bahru Electrified Double Track Project

The span term in the Overhead Catenary System (OCS) refers to the distance between two subsequent supports in the running track direction. Longer spans are preferable for economic reasons because they reduce the number of supporting structures. The maximum span along the track was suggested by OCS designers using a structure spacing table and chart with varying wind speeds and radius of curvature. The structure spacing chart is a logarithmic curve that is plotted based on the specifications of the project and design constraints. According to the current design, the maximum span length for the Gemas-Johor Bahru Electrified Double Track Project is 72 metres (GJBEDTP). The current OCS design can be upgraded to provide a greater maximum span. This study looked at the economic benefits of increasing the maximum span length of the GJBEDTP in terms of reducing the total number of supporting structures. The track is separated into many equal-length track sections, and their individual spans are selected using the wind study assessment report and the structure spacing chart. Divide the total track length by the average span to get the estimated total number of supporting structures. In this study, a graph showing the percentage of cost savings and the maximum allowable span is plotted. In this optimization issue, the Elbow approach is used to select a point where diminishing returns are no longer worth the extra expense of going for a longer span. According to the results, the maximum span of 72 m is the ideal span for the GJBEDTP.

Wide Field of View Under-Panel Optical Lens Design for Fingerprint Recognition of Smartphone.

Fingerprint recognition is a widely used biometric authentication method in LED-backlight smartphones. Due to the increasing demand for full-screen smartphones, under-display fingerprint recognition has become a popular trend. In this paper, we propose a design of an optical fingerprint recognition lens for under-display smartphones. The lens is composed of three plastic aspheric lenses, with an effective focal length (EFL) of 0.61 mm, a field of view (FOV) of 126°, and a total track length (TTL) of 2.54 mm. The image quality of the lens meets the target specifications, with MTF over 80% in the center FOV and over 70% in the 0.7 FOV, distortion less than 8% at an image height of 1.0 mm, and relative illumination (RI) greater than 25% at an image height of 1.0 mm. The lens also meets the current industry standards in terms of tolerance sensitivity and Monte Carlo analysis.

Research on the Optimization of Multibeam Bathymetry Survey Line Layout Based on Simulated Annealing Algorithm

Multibeam bathymetry systems are widely used in water depth measurement, and their principle is based on the propagation characteristics of sound waves in water. The system has multiple advantages, such as high resolution, high accuracy, wide measurement range, automated mapping, and high efficiency. This study is based on the propagation characteristics of sound waves in water and utilizes a multibeam bathymetry system for water depth measurement, focusing on key issues such as coverage width, survey path, and seawater depth. Based on a two-dimensional plane model, the direction of the emitted beams from the measurement vessel and the relationship with seafloor slope angles are considered. The key parameter calculation model of the multibeam bathymetry system is established using the sine theorem and cosine theorem. To enhance the analysis accuracy, the calculation model is extended to three dimensions, incorporating more factors that have a significant impact on the measurement, such as the slope angle along the survey lines and changes in water depth. In practical applications, the survey lines are set to run in a north-south direction, and a greedy algorithm is used to ensure complete coverage of the measurements. Taking into account the complex seafloor topography, the fitted lines are used to represent the seafloor slopes. The multi-objective programming model is transformed into an unconstrained single-objective programming problem for further optimization. By solving the problem using simulated annealing algorithm, the optimized solution provides specific values for the spacing between adjacent survey lines, total track length, missed coverage rate of the surveyed area, and duplicate measurement coverage, enabling the optimal utilization of multibeam bathymetry systems in oceanic surveys.

Maternal exposure to bisphenol S reduces anxiety and impairs collective antipredator behavior of male zebrafish (Danio rerio) offspring through dysregulation of their serotonergic system

Bisphenol S (BPS) is a common endocrine-disrupting chemical globally used in several consumer and industrial products. Although previous studies suggested that BPS induces multiple effects in exposed organisms, very little is known about its intergenerational effect on offspring behavior and/or the potential underlying mechanisms. To this end, adult female zebrafish Danio rerio were exposed to BPS (0, 10, 30 µg/L) and 1 µg/L of 17-β-estradiol (E2) as a positive control for 60 days. Afterwards, female fish were bred with untreated males, and their offspring were raised to 6 months old in control water. Maternal exposure to BPS decreased male offspring anxiety and antipredator behaviors while boldness remained unaffected. Specifically, maternal exposure to 10 and 30 µg/L BPS and 1 µg/L E2 were found to impact male offspring anxiety levels as they decreased the total time that individuals spent in the dark zone in the light/dark box test and increased the total track length in the center of the open field test. In addition, maternal exposure to all concentrations of BPS and E2 disrupted antipredator responses of male offspring by decreasing shoal cohesion in the presence of chemical alarm cues derived from conspecifics, which communicated high risk. To elucidate the possible molecular mechanism underlying these neuro-behavioral effects of BPS, we assessed the serotonergic system via changes in mRNA expression of serotonin receptors, including the 5-HT1A, 5-HT1B, and 5-HT1D subtypes, the serotonin transporter and monoamine oxidase (MAO). The impaired anxiety and antipredator responses were associated with reduced levels of 5-HT1A subtype and MAO mRNA expression within the brain of adult male offspring. Collectively, the results of this study demonstrate that maternal exposure to environmental concentrations of BPS can interfere with the serotonergic signaling pathway in the developing brain, subsequently leading to the onset of a suite of behavioral deficits in adult offspring.

Observable Large-Scale Impacts of Tropical Cyclones on the Subtropical Gyre

Abstract The large-scale ocean circulation in an ocean basin was previously thought to be impacted cumulatively by all the overlying tropical cyclones (TCs). Based on idealized numerical experiments and altimetry observation, this study reveals that, unnecessarily by cumulative impacts, a single TC actually has the ability to plow the large-scale sea surface height (SSH) field due to the TC-induced geostrophic response. This ability is dictated by the along-track length scale of the geostrophic response, i.e., the total track length. Some of the observed along-track signals, including the SSH trough, jet, and SSH rise, can confirm the TC-induced large-scale impacts. Shortly after the TC passage, the observable large-scale signals are generally the SSH trough. However, the jet and the SSH rise easily emerge from the evolved SSH trough due to Rossby wave dispersion. By identifying and tracking the observable signals, this study demonstrates that the subtropical gyre primarily over 4°–20°N, 122°E–180° is plowed by nine typhoons (2015) into several large blocks of SSH troughs and SSH rises. These long-lived SSH troughs and SSH rises dominate the upper-layer circulation from April to December in 2015. If the large-scale signals cannot be observed, the estimated TC-induced mean SSH decreases suggest that the large-scale impacts may still exist but merely cannot be seen intuitively. This study provides compelling observational evidence for the TC-induced large-scale impacts, further highlighting that TCs may play a nonnegligible role in the upper-ocean dynamics in the subtropical gyre. Significance Statement This study aims to demonstrate the ability of a typhoon to affect the large-scale ocean dynamics. The ability manifests as some along-track signals in altimetry observations, including sea surface height trough, jet, and sea surface height rise, which can be frequently observed after some typhoons in 2015. The sea surface height field in the western North Pacific is continuously plowed by these typhoons into several large blocks of sea surface height troughs and rises. These long-lived sea surface height troughs and rises dominate the upper-layer circulation from April to December in 2015. This study indicates that typhoons play a vital role in the upper-ocean dynamics in the western North Pacific.

Inverse-Designed Multi-Level Diffractive Doublet for Wide Field-of-View Imaging

Wide field-of-view (WFOV) imaging is extensively used in fields as diverse as macro photography, virtual reality, machine vision, and microscopy. Conventional WFOV cameras are bulky since they require multiple refractive lenses. Here, we design, fabricate, and characterize a 100° FOV camera with a total-track length of ∼2 mm, composed of an inverse-designed multi-level diffractive doublet with an input-aperture diameter of 0.204 mm, a back-focal length of 1 mm, and operating at λ = 850 nm (bandwidth ∼ 34 nm). Using careful experiments, we characterize the focusing and imaging performance as well as demonstrate de-vignetting based on experimental calibration. The spatial frequency at 10% modulation-transfer-function contrast was measured at 150 and 38 lp/mm for 0 and 50° incident angles, respectively. Our approach can be scaled to larger aperture sizes and smaller f/#s, potentially leading to thin, lightweight WFOV cameras for portable applications.

Impact of Body Mass Index on Static Postural Control in Adults With and Without Diabetes: A Cross-Sectional Study.

AimThe objective of this research was to determine the static postural control differences measured from a force platform in Type 2 diabetes mellitus (T2DM) and healthy control groups with different levels of body mass index (BMI), and detect the static postural control difference between T2DM and healthy control groups stratified by different BMI category. This research also explored the relationship of BMI and static postural performance.MethodsWe recruited 706 participants with T2DM and 692 healthy controls who were sufficiently matched for age, gender, and BMI in this cross-sectional study. The participants were stratified into three groups by BMI: normal weight, overweight, and obesity. All participants performed two-legged static stance postural control assessment on a firm force platform. The Center of Pressure (CoP) parameters were collected under eyes-open and eyes-closed conditions. Mann–Whitney U test was used to compare the static postural control parameters within each BMI category in both groups. The static postural control parameters among different weight groups were compared by Kruskal–Wallis test, post hoc pair-wise comparison were conducted. Generalized linear model was conducted to examine the association between BMI and static postural control parameters while controlling for confounding factors.ResultsHealthy control group had statistical difference in most CoP parameters compared to T2DM group based on all BMI categories. Normal weight participants presented significant difference compared with overweight and/or obesity for total track length (TTL) and velocity of CoP displacements in Y direction (V-Y) under eyes-open condition, and for most CoP parameters under eyes-closed condition in both groups. There were statistically significant correlations between BMI and most static postural control parameters under only eyes-closed condition according to the result of generalized linear model.ConclusionT2DM patients had impaired static postural control performance compared to healthy controls at all BMI categories. The findings also indicated the association between BMI and static postural control, where higher BMI individuals showed more static postural instability in both T2DM and healthy controls.

Techno-economic analysis of energy supply to personal rapid transit (PRT) systems

Personal Rapid Transit (PRT) is an innovative form of urban transportation which might provide an alternative to car use. PRT is conceptualized by an array of autonomous pods, providing shared riding service to a small number of travelers per vehicle, on a dedicated guideway. PRT is considered by many to be a travel mode that reduces energy use and emissions levels, compared with traditional cars. To evaluate the cost effectiveness and benefits associated with the energy consumed by a typical urban PRT system, a detailed techno-economic analysis of two energy supply alternatives is presented. The technologies considered are: battery storage and third-rail conductors. This paper demonstrates a methodological approach to evaluate PRT energy costs, illustrated by a case study: the city of Herzliya (ISR). First, a PRT system model was developed, including both infrastructure design and operational characteristics, with a total track length of 12.5 km. Then, vehicles tractive and grid energy requirements were derived from the case study data using rigid body mechanics and lumped powertrain properties. Following, an economic evaluation was carried out taking into account capital costs as well as operating costs based on tractive, auxiliary and parasitic energy requirements. In both cases, the energy consumption is about 0.08 [kWh/p-km], while the energy costs are 0.031 and 0.100 [$/p-km] for the battery and third rail, respectively. Future research is discussed in the directions of further modeling development and extending the scope of alternatives.

Effects of the implementation of a mass rapid transit system on mortality rates attributed to cardiorespiratory complications in Taipei

ABSTRACT Although Taipei City has encountered a fall in ambient air pollutant levels since 1996, the year its mass rapid transit (MRT) system commenced operation, no apparent study investigated changes in risks of death attributed to respiratory, cardiovascular, and cerebrovascular diseases in Taipei during this 23-year period. In order to examine the relationship between MRT and occurrence of respiratory and cardiovascular illnesses attributed to air contaminants, exposure over the 23 year duration was subdivided into the following periods: reference period 1 (1992–1995); period 2 (1996–2004), a time when there was a total track length of 67 km; period 3 (2005–2015), when the total track length was lengthened to 131.1 km; and period 4 (2016–2020), when it was further extended to 146.2 km. Taichung City, no MRT system, was used as an external reference population. The effect of Taipei’s MRT system on rates of cause-specific death rates was analyzed using robust generalized Poisson regression models. After adjusting for age-standardized rates (ASRs), a decrease in relative risks (RRs) was found for non-trauma death and respiratory disease from periods 2 to 4. Even though the RRs were greater than 1.0 for cardiovascular and cerebrovascular diseases for periods 2 to 4, a downward trend was still noted in these RRs in Taipei. These findings suggest a relationship exists between air pollutant exposure and mortality. In addition, data demonstrated that implementation of the MRT in Taipei exerted beneficial health effects as evidenced by lower mortality rates.

High Contrast Ultrathin Light‐Field Camera Using Inverted Microlens Arrays with Metal–Insulator–Metal Optical Absorber

AbstractLight‐field imaging has attracted much attention in constructing 3D objects with a simple configuration and capturing all the spatial and directional data in a single photographic exposure. Here, an ultrathin light‐field camera (ULFC) for high contrast and high‐resolution light‐field imaging using a metal–insulator–metal optical absorber based inverted microlens arrays (MIM‐iMLA) is reported. A metal–insulator–metal based optical absorber (MIM‐OA) between microlenses exhibits high light absorption in the full visible region, thereby highly blocking microlens crosstalk. The MIM‐iMLA double the image contrast and improve MTF50 by up to 32%, compared to conventional light‐field image. In addition, the MIM‐iMLA substantially reduces an image plane distance and brings the objective lens position closer to the MLA. The ULFC exhibits a short total track length of 5.1 mm, demonstrating high contrast light‐field image acquisition and high accuracy 3D depth map estimation after light‐field rendering. This ultrathin and high contrast light‐field camera can provide a new platform for miniaturized 3D cameras in biomedical applications, biometrics, automated inspection, or mobile camera applications.

Change in risk of hospital admissions for ischemic heart disease after the implementation of a mass rapid transit system in Taipei

ABSTRACT Numerous epidemiologic studies demonstrated an association between an increase in levels of fine particles (particulate matter less than 2.5 um in diameter, PM2.5) and elevation in the number of hospital admissions for cardiovascular diseases. Air pollution levels including PM2.5 clearly decreased in Taipei City after the mass rapid transit (MRT) system began operations in 1996. The aim of this study was to investigate the extent of changes in the risk of daily hospital admissions for ischemic heart disease (IHD) over a 17-year period after the installation of a MRT system in Taipei. The full study was divided into Period 1 (1997–2000), total track length 65.1 km; Period 2 (2001–2008), total track length 75.8 km; and Period 3 (2009–2013), total track length 121.3 km. A time-stratified case-crossover analysis was conducted to estimate relative risk (RR) of hospital admissions for IHD for each 10 ug/m3 increase in PM2.5 for different periods. On cool days, the associated RR of IHD for Period 3 was consistently lower compared to period 2 in both our single- and two-pollutant models. However, the daily risk for IHD admissions was found to be significantly higher for period 3 compared to period 2 in our single-pollutant model and in our two-pollutant models (PM2.5+ SO2) on warm days. The basis for this difference is unknown. Data suggests that an MRT system may provide substantial health benefits, a finding that may be helpful to urban communities, urban planners, and public health specialists.

Path Planning Algorithm of Dijkstra-Based Intelligent Aircraft under Multiple Constraints

Aiming at the rapid planning of the optimal flight path of the intelligent aircraft, considering the error constraints and correction probability constraints, a model for intelligent aircraft path planning under multiple constraints is constructed, and a global search algorithm based on Dijkstra algorithm is proposed to solve the model. By calculating the residual error and restricts flight distance, the basic Dijkstra algorithm is improved to make it more adaptable to solve the path planning under multiple constraints. At the same time, simulation experiment is conducted with the optimal goal of the shortest track length and satisfying the error constraints. The experimental results show that the aircraft passed a total of 18 correction points when it reached the destination. The total track length was 144 287.932 m, the vertical position error was 17.254 units, and the horizontal position error was 6.420 units. The results meet the error requirements. The results show that the intelligent aircraft path planning model and Dijkstra-based global search algorithm with multiple constraints are reasonable in solving such problems.

Compact wide-angle capsule endoscopic lens design.

Capsule endoscopes require a high-quality imaging system in terms of the wide field of view (FOV), image brightness, and resolution to provide accurate diagnostic information. However, because of the wide-angle lens design, the first element of the lens inevitably becomes larger in diameter, making it difficult to reduce the overall size of the lens. In this study, the compact wide-angle lens for a capsule endoscope is reported. The proposed system allows the first element to be compact in diameter and increases image quality by utilizing all aspheric surfaces for optical aberration control. The specification of the proposed capsule endoscope lens shows the wide FOV of 160 deg, F-number 2.8, and total track length of 5 mm. In the overall FOV, relative illumination is still over 60%. To achieve a high image quality in the proposed system, the modulation transfer function is over 30% at 180 lp/mm for a${1920} \times {1080}$1920×1080 1/6 inch CMOS image sensor in a pixel size of 1.4 µm.

Discrete- and Continuous-State Trajectory Decoders for Positioning in Wireless Networks

The need for accurate positioning and tracking of mobile sensor nodes arises in many applications. To compute position estimates from raw measurements in positioning systems, Bayesian filtering techniques such as Kalman, histogram, or particle filters are frequently employed. A major disadvantage of these techniques is the fact that they compute only a single position estimate in every timestep and, therefore, do not utilize the available information to the full extent. The work presented in this article improves over this current state of the art by instead estimating full node trajectories and, therefore, the most plausible sequence of positions in every timestep. We present two distinct algorithms—for a discrete and for a continuous state-space—and highlight the particular advantages of each variant. Achievable results are shown by simulation and measurement to be more accurate than the traditional Bayesian filtering approach. The most prominent advantage of much more accurate total track length estimation is particularly emphasized.

THE PHYSIOLOGICAL RESPONSE TO BEE HONEY APPLICATION IN BROILER CHICKEN DIETS

The aim of the present study was to investigate the effects of Bee Honey (BH) on broiler chicken carcass characteristics, digestive tract length, immune organs weight, villi development and blood plasma parameters. A total number of 120 one-day old Cobb broiler chicks were randomly assigned to four dietary treatments, three replicates of 10 chicks each. A basal diet (control group) was supplemented with 3 levels of (BH, T1-3) 0.10, 0.15 and 0.20% respectively. The carcass characteristics were measured, and blood plasma samples were collected for analyses of total protein, albumin, cholesterol, triglyceride, AST, ALT, calcium and phosphorus. The length measurements were performed for total digestive tract and small intestine. The weights of bursa, spleen and ileal morphology were also measured. The results showed that there were no significant differences within treatments for carcass %, total edible parts %, total digestive track and small intestine length (cm/ 100 g body weight) and bursa mass %. However, BH affected spleen %, increased villi height, muscle thickness and goblet cell numbers and decreased villi width. Analysis of the blood plasma indicated no influence of BH addition on albumin, cholesterol, calcium and phosphorus concentrations. However, decreased A/G ratio, triglyceride, AST and ALT and increased total protein and globulin levels, were observed in BH-treated groups. In conclusion, BH supplementation to broiler diets had a significantly positive effects on villi development with no negative influence on chicken metabolism and immune response.

Optical design of a 2× zoom lens for miniature imaging systems

The optical design of a compact 2 × zoom lens in a lens barrel for miniature cameras is reported. The magnification in the optical system is achieved by means of changing positions of lens elements inside the lens barrel. Six lens elements are employed in the optical system, where up to four elements are actuated. Maximum travel distances for the moving parts are determined as 1.67 mm to reach a magnification of 2.06 × , and the total track length for the telephoto zoom lens state is 9.16 mm at its most extended configuration. Manufacturability of the proposed system is also discussed using a tolerance analysis. The designed optical system is suitable for use with image sensors up to 13 MP, and it can be employed in an endoscopic camera, where the optical zoom and compact design are beneficial. It is also suitable for smartphone cameras with further enhancements and integration of voice-coil-motors and/or MEMS actuators.

Flying south: Foraging locations of the Hutton's shearwater (Puffinus huttoni) revealed by Time-Depth Recorders and GPS tracking.

The Hutton's shearwater Puffinus huttoni is an endangered seabird endemic to Kaikōura, New Zealand, but the spatial and temporal aspects of its at‐sea foraging behavior are not well known.To identify foraging areas and estimate trip durations, we deployed Global Positioning Systems (GPS) devices and Time‐Depth Recorders (TDR) on 26 adult Hutton's shearwaters during the chick‐rearing period in 2017 and 2018.We found Hutton's shearwaters traveled much further from their breeding grounds at Kaikōura than previously considered, with most individuals foraging in coastal and oceanic areas 125–365 km south and near Banks Peninsula. Trip durations varied from 1 to 15 days (mean = 5 days), and total track lengths varied from 264 to 2,157 km (mean = 1092.9 km).Although some diving occurred in near‐shore waters near the breeding colony, most foraging was concentrated in four regions south of Kaikōura. Dive durations averaged 23.2 s (range 8.1 to 71.3 s) and dive depths averaged 7.1 m (range 1.5 to 30 m). Foraging locations had higher chlorophyll a levels and shallower water depths than nonforaging locations. Birds did not feed at night, but tended to raft in areas with deeper water than foraging locations.Mapping the spatial and temporal distribution of Hutton's shearwaters at sea will be fundamental to their conservation, as it can reveal potential areas of overlap with fisheries and other industrial users of the marine environment.