Line Method Research Articles

Particle Deposition Distribution of Multi-Rotor UAV-Based Fertilizer Spreader under Different Height and Speed Parameters

As an effective supplement to ground machinery, UAVs play an important role in agriculture and have become indispensable intelligent equipment in the development of precision agriculture. Various types of agricultural UAV-based spreading devices, mainly disc-type and pneumatic-type, have appeared in domestic and foreign markets. UAV-based rice topdressing has gradually become a widely recognized application with great market potential. In the process of UAV-based low-altitude fertilization, due to the existence of the rotor wind field, the environment for particle air diffusion is complex, and the movement trajectory and deposition distribution of fertilizer are affected by many factors, resulting in large differences in the spreading. The flight height and speed have a great influence on particle movement and deposition, and a reasonable combination of work parameters can be used for efficient and high-quality particle deposition. In order to obtain better particle deposition distribution, this paper uses the method of a single flight line to test and analyze the characteristics of particle deposition distribution for fertilization using multi-rotor UAVs at different flight heights and speeds. The effective swath width and deposition uniformity obtained via the simulation of overlapped route superposition were used to optimized the appropriate work parameters to ensure that a reasonable and effective deposition amount can be obtained during actual application. The results show that the flight height and speed and the interaction of both have an important influence on the deposition amount and the effective width, but it is not a simple linear relationship. On the whole, as the flight height increases, the coefficient of variation decreases and the effective width increases, but it is not obvious when the speed is low. For the R20, when the flight speed is 2 m/s, the effective width first increases and then decreases with the increase in flight height, and the difference in the deposition amount at a height of 5 m is larger than that at other heights. Under the three working heights, the effective swath width is the same when the flight speed is 4 m/s and 6 m/s, and the effective swath width is also the same when the speed is 7 m and 9 m. For the T16, when the flight speed is 4 m/s, the deposition uniformity is relatively good, and the effective width increases with the increase in flight height. Therefore, the combination of 7–6 m/s and 9–4 m/s parameters will be the best operating parameters for R20 and T16. However, considering the actual dynamic meteorological environment in the field, the operating height can be appropriately lowered according to the influence of the crosswind during actual operation. The research results of this paper can provide scientific reference and suggestions for further improving the effect of UAV-based fertilization.

A Novel Calibration Method of Line Structured Light Plane Using Spatial Geometry.

The line structured light plane calibration method using a plane target cannot produce satisfactory calibration results due to inaccurate positioning of the calibrated points. Field of view noise and sensor noise affect the target light stripe extraction and camera parameter calculation during the calibration process. These factors will cause the calculation of the coordinates of the calibrated point to deviate, and thus affect the light plane calibration. To solve this problem, we propose a new method to calculate the calibrated point based on spatial geometry. Firstly, for the projection line corresponding to the feature point on the light stripe and the corresponding line on the target, a common perpendicular of these two lines above is established, and since the sum of the squares of the distances from the midpoint to the two straight lines is the smallest, the midpoint of the common perpendicular is taken as the calibrated point. Secondly, the target is moved to different positions, and the non-collinear calibrated points are calculated. Finally, the parameters of the light plane are obtained by fitting these calibrated points. This method requires only a checkerboard target, and has a simple calibration process. The experimental results show that the average error of the calibration method proposed in this paper is 0.011 mm, which is less than the 0.031 mm of the calibration method based on the plane target with cross-ratio invariant.

Artificial Intelligence Automation of Proptosis Measurement: An Indicator for Pediatric Orbital Abscess Surgery.

To evaluate the ability of artificial intelligence (AI) software to quantify proptosis for identifying patients who need surgical drainage. We pursued a retrospective study including 56 subjects with a clinical diagnosis of subperiosteal orbital abscess (SPOA) secondary to sinusitis at a tertiary pediatric hospital from 2002 to 2016. AI computer software was developed to perform 3D visualization and quantitative assessment of proptosis from computed tomography (CT) images acquired at the time of hospital admission. The AI software automatically computed linear and volume metrics of proptosis to provide more practice-consistent and informative measures. Two experienced physicians independently measured proptosis using the interzygomatic line method on axial CT images. The AI software and physician proptosis assessments were evaluated for association with eventual treatment procedures as standalone markers and in combination with the standard predictors. To treat the SPOA, 31 of 56 (55%) children underwent surgical intervention, including 18 early surgeries (performed within 24h of admission), and 25 (45%) were managed medically. The physician measurements of proptosis were strongly correlated (Spearman r = 0.89, 95%CI 0.82-0.93) with 95% limits of agreement of ± 1.8mm. The AI linear measurement was on average 1.2mm larger (p = 0.007) and only moderately correlated with the average physicians' measurements (r = 0.53, 95%CI 0.31-0.69). Increased proptosis of both AI volumetric and linear measurements were moderately predictive of surgery (AUCs of 0.79, 95%CI 0.68-0.91, and 0.78, 95%CI 0.65-0.90, respectively) with the average physician measurement being poorly to fairly predictive (AUC of 0.70, 95%CI 0.56-0.84). The AI proptosis measures were also significantly greater in the early as compared to the late surgery groups (p = 0.02, and p = 0.04, respectively). The surgical and medical groups showed a substantial difference in the abscess volume (p < 0.001). AI proptosis measures significantly differed from physician assessments and showed a good overall ability to predict the eventual treatment. The volumetric AI proptosis measurement significantly improved the ability to predict the likelihood of surgery compared to abscess volume alone. Further studies are needed to better characterize and incorporate the AI proptosis measurements for assisting in clinical decision-making.

Habitat and behavior of javan hawk-eagle (Nisaetus bartelsi) in SPTN 2 Majelengka Gunung Ciremai National Park, West Java

The existence of the Javan hawk-eagle depends on the condition of the forest in its habitat. If the lowland forest is damaged, the Javan hawk-eagle will be pushed to the higher forest; This can affect the behavior of the Javan hawk-eagle because it is related to the availability of the game in each habitat type. This study aims to analyze the habitat conditions and behavior of the Javan hawk-eagle in Mount Ciremai National Park, using the checkered line method and focal animal sampling. Analysis of the Javan hawk-eagle habitat used a vegetation analysis approach and the level of use of habitat types. The results showed that the Javan hawk-eagle most often used natural forest habitat types (85.38%) at the Cipari site and plantation forests (83.14%) at the Bantar agung site. The dominant tree species in the natural forest are benda (Castanopsis argentea; 20.02%) and saninten (Artocarpus elasticus; 13.30%). Javan hawk-eagles choose trees to nest in kedondong trees (Spondias pinnata) and pine trees (Pinus merkusii ) in valleys between hills and close to water sources or rivers. Overall the behavior of the Javan hawk-eagle found is resting/perching, hunting, flying, and interacting. The most common behavior of Javan hawk-eagles found was resting/perching (80.16%) and interaction (45.88%).

Perancangan Sistem Antrian Berbasis Web Pada Puskesmas Pangolombian

This study designed and implemented a web-based queuing system at the Pangolombian Health Center. The method applied is the waiting line method with the waterfall system development method. This system uses PHP and MySQL as the programming language and database. Key features include patient registration, scheduling, calling, and real-time queue status display. After implementation, functionality and performance testing is carried out. The results show that this web-based queuing system improves efficiency and patient experience. Patients can register and schedule queues online, reducing waiting times. Automatic queue calling makes it easier for puskesmas staff. Staff and schedule management features help manage queues more efficiently. This research produces an efficient and convenient web-based queuing system. This system has the potential to provide a better experience for patients by reducing waiting times and long queues. This system also assists puskesmas staff in managing queues efficiently. The results of this study can contribute to developing a web-based queuing system at puskesmas and other health institutions

Appraising the dielectric properties and the effectiveness of electromagnetic shielding of graphene reinforced silicone rubber nanocomposite

Abstract The aim of this research is to measure the dielectric properties and electromagnetic interference (EMI) shielding effectiveness (SE) of silicone rubber reinforced with graphene nanoplates. In a two-roll mill, different amounts of graphene are mixed together. This is followed by compression moulding at 170°C and post-curing for 4 h at 200°C. Between 1 MHz and 1 GHz, the waveguide transmission line method and a vector network analyser are used to measure the dielectric and EMI SE parameters. As the amount of graphene is increased from 0 to 7 wt%, AC conductivity goes up, reaching 1.19 × 10−3 S/cm at 7 wt%. The same composition gives the highest EMI SE of 43.22 dB at 1 GHz. The high-frequency structural simulation of different compositions shows how shielding works, and the results agree with what has been seen in experiments.

Selection of TCC Curve and Protection Cooperation Method of Distribution Line Using Linear Optimization

Distribution systems are mostly composed of radial structures, which are susceptible to an increased variability and complexity of system operation due to frequent line changes during operation. When multiple changes in distribution lines occur simultaneously, the relative positions of protective devices also change. The existing protection coordination method of distribution lines is configured by considering the operation characteristics and coordination time interval (CTI) of all protective devices in series from the substation to the terminal load. Therefore, the protection coordination algorithm needs to be redesigned whenever a line is changed or a protective device is added to the distribution line for which the existing protection coordination algorithm has been set. In addition, existing protection coordination methods require complex calculations and procedures, which are subject to human errors and are less feasible for responding in real-time to changes in the distribution system. In this paper, we propose the adaptive time–current curve (TCC) method by selecting the time dial setting (TDS) and minimum response time (MRT) of individual protective devices in accordance with the relative distance based on the linear optimization technique. Using PSCAD/EMTDC, a power system analysis program, the minimum operating current and the fault current of each protective device are obtained, and the proposed protection coordination algorithm is verified according to the series configuration relationship of the protective devices. Finally, the proposed method is applied to an actual distribution line to verify the improvement over the existing protection coordination.

The assessment of a fast computational method in predicting the unsteady loads of vertical axis wind turbines undergoing floating motion

The low center of gravity and low center of thrust of Vertical Axis Wind Turbines (VAWT) are interesting characteristics when considering Floating-Offshore Wind Turbine (FOWT) application. The motion due to the floating platform adds extra complexity to the unsteady aerodynamics of VAWT. Hence, both numerical and experimental studies become very challenging. This paper focuses on the assessment of TubinesFoam, a fast tool consisting of the actuator line method (ALM) embedded in OpenFoam. Then, instead the typical bladed-solved Navier–Stokes equations, the ALM inserts the blade forces into the field as body forces into the momentum equation. A modified version of the turbinesFoam library that includes surge motion for multiple rotors has been evaluated by comparison with an experimental set of data from a twin-rotor performing surge in a wind tunnel. This paper includes the main equations describing the kinematics implemented in the numerical code, as well as a convergence analysis of mesh size, time step and surge cycles. The numerically predicted thrust forces agreed with the experimental results for both investigated tip speed ratios for the case with no surge motion. The numerical and experiment results including surge motion indicated a minimal influence of the surge motion for the cases evaluated here. The last verification using CFD computations from the literature showed that the turbinesFoam tool properly captures the main features of the surge motion. This verified numerical method is a promising tool to understand the effects of geometrical parameters on the performance and the wake development of VAWTs farms in floating-offshore environments.

An accurate fault location method for distribution lines based on data fusion of outcomes from multiple algorithms

Accurate fault location technology for distribution lines is of great importance as it can shorten power outage time and enhance power supply reliability. Current and voltage transformer errors and line parameter errors will result in location error of the existing algorithms, which cannot meet the requirements of power supply reliability. To solve this problem, a data-fusion model based on multiple algorithms is proposed in this study, which makes full use of the location results of existing algorithms. First, the complementarity among the four selected algorithms is analyzed. Then the feasibility of improving fault location accuracy by constructing a data-fusion model is explained and the overall structure of the data-fusion model is determined. Finally, an artificial neural network with a strong fitting ability is used to complete the construction of the data-fusion model. The performance of the model is tested for different factors, such as fault positions, line parameters, fault resistances, and fault inception angles. The test cases based on PSCAD/EMTDC show that the constructed model has excellent generalization ability. Additionally, performance of the model is not affected by distributed generation and sampling rate. The proposed method does not use high-sampling devices and is cost-effective.

PLPose: An efficient framework for detecting power lines via key points-based pose estimation

The inspection and maintenance of electrical power lines (PL) via unmanned aerial vehicles (UAV) require fast and accurate PL detection to ensure smooth and secure electrical operations. However, the detection of PLs from aerial images is a highly challenging task due to the thin nature of PLs and the inherent noisy image backgrounds. Traditional line and edge detection methods do not detect the PLs accurately due to the cluttered backgrounds while the more recent deep learning (DL) CNNs are also not feasible for efficient PL detection due to the coarse bounding boxes and the computationally expensive pixel-based segmentations. Hence, in this study we propose PLPose, a novel framework for detecting the PLs via key points-based pose estimation technique and adapt the MobileNetV3 CNN for this task (kMobileNetV3), by adding a simple key point detection head to predict the PL key points. We also introduce a novel data-centric architecture (kMobileNetV3 + UDP), by adding the unbiased data processing (UDP) module to our kMobileNetV3, for faster and more accurate key point-based PL detection along with novel methods for data annotations and performance evaluation. Evaluations of PLPose on three benchmark PL datasets (PLDM, PLDU and the Mendeley Powerline Dataset) reveal that our proposed framework outperforms the state-of-the-art top-down pose estimation networks (HRNet-w32, HRNet-w32 + UDP and Resnet-50 Simple Baselines) in processing speed (∼29 FPS) and model size (5.23 M) for PL detection. Thus, the comprehensive experimental results demonstrate the effectiveness of our proposed framework. Our code is available from Github (https://www.github.com/rubeea/pl_mmpose).

Single-ended protection method for hybrid HVDC transmission line based on transient voltage characteristic frequency band

Hybrid high-voltage direct current (HVDC) transmission has the characteristic of long transmission distance, complex corridor environment, and rapid fault evolution of direct current (DC) lines. As high fault current can easily cause irreversible damage to power devices, rapid and reliable line protection and isolation are necessary to improve the security and reliability of hybrid HVDC transmission system. To address such requirement, this paper proposes a single-ended protection method based on transient voltage frequency band characteristics. First, the frequency characteristics of the smoothing reactor, DC filter, and DC line are analyzed, and the characteristic frequency band is defined. A fault criterion is then constructed based on the voltage characteristic frequency band energy, and faulty pole selection is performed according to the fault voltage characteristic frequency band energy ratio. The proposed protection method is verified by simulation, and the results show that it can rapidly and reliably identify internal and external faults, accurately select faulty poles without data communication synchronization, and has good fault-resistance and anti-interference performance.

Impact of sand bund removal on seagrass ecosystems: A study of macrobenthic community structure and correlation with macrophytes cover and sediments

This study investigated the impacts of the removal of sand bund on the macrobenthos community structure, seagrass cover, and sediment particle size in Merambong Shoal, Malaysia. The reclamation project deposited sand bund in the middle of Merambong seagrass shoal, resulting in its division into northern (NS) and southern (SS) halves. Ecosystem changes were monitored over a 31-month period using the transect lines method. Bi-monthly samples were collected for assessment. The results revealed a substantial decline in macrobenthos densities compared to previous studies. However, after the removal of the sand bund, there was a significant increase in macrobenthos density, specifically Polychaeta and Malacostraca, at NS. Seagrass cover at NS was initially lower than SS but showed an increase after the complete removal of the sand blockage. Sediment particle analysis reported a higher silt percentage at NS, indicating greater sedimentation at NS, which was partially sheltered from wave actions.

Visual Detection Method for Missing Infusion Bag Pipeline

As an essential medical device, a bag infusion set is often used for intravenous infusion, and an infusion bag is an essential part of the bag infusion set. Due to the unavoidable defects in the production process, quality detection of infusion bags is critical to ensure the use quality of the infusion set. In this paper, we adopt a machine vision system to inspect the assembly quality of the lanyard and dosing interface of liquid bag assembly and conduct in-depth discussion and research from image acquisition, a defect detection strategy, and a defect detection algorithm of a vision system for two defects of lanyard missing and dosing interface missing. The design of the image acquisition auxiliary mechanism is realized to solve the complex problem of image acquisition due to the irregular shape of the liquid bag assembly; based on determining the defect detection strategy, the algorithm study of contour extraction is finally completed through comparison experiments to extract a precise contour of the liquid bag piping area; finally, the virtual straight line method is proposed and combined with the ROI selected according to the position feature of the outer rectangle of the contour in this paper, the count of the number of contours is completed, and the defect detection goal is finally achieved. The pipeline defect detection rate of the method proposed in this paper reaches 100%, which can perfectly replace the existing manual visual inspection and reduce the employment cost of enterprises.

Identifying the Optimal Radiometric Calibration Method for UAV-Based Multispectral Imaging

The development of UAVs and multispectral cameras has led to remote sensing applications with unprecedented spatial resolution. However, uncertainty remains on the radiometric calibration process for converting raw images to surface reflectance. Several calibration methods exist, but the advantages and disadvantages of each are not well understood. We performed an empirical analysis of five different methods for calibrating a 10-band multispectral camera, the MicaSense RedEdge MX Dual Camera System, by comparing multispectral images with spectrometer measurements taken in the field on the same day. Two datasets were collected, one in clear-sky and one in overcast conditions on the same field. We found that the empirical line method (ELM), using multiple radiometric reference targets imaged at mission altitude performed best in terms of bias and RMSE. However, two user-friendly commercial solutions relying on one single grey reference panel were only slightly less accurate and resulted in sufficiently accurate reflectance maps for most applications, particularly in clear-sky conditions. In overcast conditions, the increase in accuracy of more elaborate methods was higher. Incorporating measurements of an integrated downwelling light sensor (DLS2) did not improve the bias nor RMSE, even in overcast conditions. Ultimately, the choice of the calibration method depends on required accuracy, time constraints and flight conditions. When the more accurate ELM is not possible, commercial, user-friendly solutions like the ones offered by Agisoft Metashape and Pix4D can be good enough.

Distance Protection for Lines Connecting Converter Interfaced Renewable Power Plants: Adaptive to Grid-end Structural Changes

Typical fault current characteristics of converter interfaced renewable power plants have significant impact on the reliability of traditional line distance protection. Large degrees of system non-homogeneity introduce substantial error in the apparent impedance calculation. In this paper, an adaptive distance relaying method for lines connected to converter-interfaced renewable power plants is proposed. A range of fault current phase angles is identified using the local and remote equivalent source impedances, which are calculated using only local measurements. Corresponding to the lower and upper bound of the identified range of fault current phase angle, two apparent impedances are calculated based on priority to dependability and security of protection operation. The trip decision is made based on the weighted sum of the first and second apparent impedances. Tuning of the dependability and security weightage factors based on the calculated remote grid-end source impedance, ensures adaptability and reliability of operation, even after structural changes in the grid. The proposed method is verified using IEEE 39 bus system and validated using field data. Comparative assessment with practically proven distance and modified distance protection method for lines connected with renewables is also provided.

EPS4.03 An audit of diagnosing cystic fibrosis-related diabetes using newly developed diagnostic criteria using flash glucose monitoring system (Freestyle Libre®) at a regional adult cystic fibrosis centre

Objectives: In 2022, the West Midlands Adult Cystic Fibrosis Centre began using Freestyle Libre flash glucose monitoring system (FGM) as a first line method for cystic fibrosis related diabetes (CFRD) screening, as an alternative to oral glucose tolerance testing (OGTT). There are no published criteria for the diagnosis of CFRD using FGM. Using the WHO criteria, the Brompton’s paediatric clinical guideline and clinical judgement we devised diagnostic criteria to standardise the diagnosis of CFRD using FGM. Diagnostic criteria - CFRD >2 readings >11.1, impaired glucose tolerance (IGT) >2 readings 7.8–11 or <3.5; over a 2 week period. The aim of this study was to compare the number of patients diagnosed with CFRD and IGT using our new FGM diagnostic criteria compared to using our previous non standardised practice of using clinical judgement. We aimed to assess if there was any difference in the number of patients being diagnosed with CFRD or IGT using our new criteria.

UM 462, a local green pea galaxy analogue under the MUSE magnifying glass

Context. Stellar feedback in high-redshift galaxies plays an important, if not dominant, role in the re-ionisation epoch of the Universe. Because of their extreme star formation (SF), the relatively closer green pea (GP) galaxies are postulated as favorite local laboratories, and analogues to those high-redshift galaxies. However, at their typical redshift of z ∼ 0.2, the most intimate interaction between stars and the surrounding interstellar medium cannot be disentangled. Detailed studies of blue compact dwarf (BCD) galaxies sharing properties with GP galaxies are necessary to anchor our investigations on them. Aims. We want to study in detail UM 462, which is a BCD with emission line ratios and equivalent widths, stellar mass, and metallicity similar to those observed in GP galaxies, and thus it is ideally suited as a corner stone and reference galaxy. Methods. We use high-quality optical integral field spectroscopy data obtained with MUSE on the ESO Very Large Telescope. Results. The electron density (ne) and temperature (Te) were mapped. Median Te decreases according to the sequence [S III] → [N II] → He I. Furthermore, Te([S III]) values are ∼13 000 K, and uniform within the uncertainties over an area of ∼20″ × 8″ (∼1.4 kpc × 0.6 kpc). The total oxygen abundance by means of the direct method is 12 + log(O/H) ∼ 8.02 and homogenous all over the galaxy within the uncertainties, which is in stark contrast with the metallicities derived from several strong line methods. This result calls for a systematic study to identify the best strategy to determine reliable metallicities at any location within a galaxy. The strong line ratios used in the BPT diagrams and other ratios tracing the ionisation structure were mapped. They are compatible with plasma ionised by massive hot stars. However, there is a systematic excess in the [O I]/Hα ratio, suggesting an additional mechanism or a complex relative configuration of gas and stars. The velocity field for the ionised gas presents receding velocities in the east and approaching velocities in the west and south-west with velocity differences of Δv ∼ 40 km s−1, but it is not compatible with simple rotation. The most striking feature is a velocity stratification in the area towards the north with redder velocities in the high ionisation lines and bluer velocities in the low ionisation lines. This is the only area with velocity dispersions clearly above the MUSE instrumental width, and it is surrounded by two ∼1 kpc-long structures nicknamed ‘the horns’. We interpret the observational evidence in that area as a fragmented super-bubble fruit of the stellar feedback and it may constitute a preferred channel through which Lyman continuum photons from the youngest generation of stars can escape. The galaxy luminosity is dominated by a young (i.e. ∼6 Myr) stellar population that contributes only 10% to the stellar mass, as derived from the modelling of the stellar continuum. The most recent SF seems to propagate from the outer to the inner parts of the galaxy, and then from east to west. We identified a supernova remnant and Wolf-Rayet stars – as traced by the red bump – that support this picture. The direction of the propagation implies the presence of younger Wolf-Rayet stars at the maximum in Hα. These may be detected by deep observations of the blue bump (not covered here). Conclusions. The ensemble of results exemplifies the potential of 2D detailed spectroscopic studies of dwarf star-forming galaxies at high spatial resolution as a key reference for similar studies on primeval galaxies.

Analytical Parasitic Resistance and Capacitance Models for Nanosheet Field-Effect Transistors

We developed analytical compact models of parasitic resistance and capacitance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> ) for nanosheet field-effect transistors (NSFETs) with metal contact structures. The proposed model accurately captures the number of sheets, sheet geometry, gate, source, drain, and contact sizes. The parasitic resistance model generated in each region was modeled using the transmission line method (TLM) and the spread resistance model. The parasitic capacitance model was modeled using the conformal mapping method based on the distribution of the electric field. The developed models were validated by changing the structural parameters. The proposed models were implemented in Berkeley short-channel IGFET model (BSIM)-common multi-gate (CMG) to enable circuit performance prediction. With our proposed model, we can accurately predict the circuit performance of NSFETs, capturing the recent scaling trends and process variations in the proposed NSFET.

Vegetation Analysis of Target Species for Feeding Lesser Yellow Bird of Paradise (Paradisaea minor jobiensis Rothschild, 1897) in the Imbowiari Forest Area of Barawai Village, Yapen Islands District, Papua Province, Indonesia

The research aims to determine the plant species, structure, and composition of the food sources of P. minor jobiensis in the Imbowiari Barawai forest area, Yapen Islands Regency. The method used in this research the method of observation, interviews, documentation, literature, and the checkered line method. Data analysis techniques used are density, dominance, frequency, relative density, relative dominance, relative frequency, important value index, and diversity index. The results of the study found 6 species of plants as food for P. minor jobiensis and spread at the level of seedlings, poles, saplings, and trees namely Elaeocarpus sphaericus, Ficus benjamina, Gnetum gnemon, Syzygium sp., Myristica sp., and Palaquium ambounense

Single longitudinal mode narrow linewidth thulium-doped fiber laser based on an eye-shaped dual-ring filter

A single-longitudinal-mode (SLM) thulium-doped fiber laser, based on an eye-shaped passive dual-ring filter, is designed and constructed. The eye-shaped passive compound cavity consisting of four couplers is used to increase the longitudinal mode spacing, and its performance is numerically analyzed in detail. A homemade uniform fiber Bragg grating serves as a wavelength selection device and a saturable absorber is used to further suppress the intense longitudinal mode competition in the laser cavity, ensuring the single-longitudinal-mode output. The experimental results demonstrate a laser output with a center wavelength of 2,049.85 nm and an optical signal-to-noise ratio of 63 dB. Moreover, the power fluctuation is less than 0.6 dB, and the center wavelength fluctuation is less than 0.03 nm over a continuous measurement period of 60 min, demonstrating an excellent stability. The laser linewidth is measured using an unbalanced Michelson interferometer and β-separation line method, resulting in a linewidth of 11.22 kHz.