Line Alignment Research Articles

Assessment of genetic diversity and heterotic alignment of CIMMYT and IITA maize inbred lines adapted to sub‐Saharan Africa

AbstractDespite the breeding efforts by many institutions, maize (Zea mays L.) productivity in sub‐Saharan Africa is still low. A limited number of productive maize hybrids have been developed partly due to a lack of knowledge on the diversity and heterotic relationship of the germplasm, especially in public breeding programs. Understanding the extent of diversity, structure, and heterotic grouping of available maize germplasm originating from different breeding programs is important to enhance long‐term genetic gain in hybrid maize breeding programs by optimizing heterotic pools using modern breeding tools. Information about the genetic structure of the available germplasm could help breeders design effective breeding strategies to improve yield. This study was conducted to determine the genetic diversity, population structure, and heterotic alignment among 187 elite maize inbred lines from the IITA (International Institute of Tropical Agriculture) and CIMMYT (International Maize and Wheat Improvement Center) maize breeding programs. The inbred lines were genotyped with 9857 Diversity Array Technology sequencing based single nucleotide polymorphism markers. Hierarchical clustering revealed three major groups, with some subgroups consistent with the selection history, and pedigree of the inbred lines. Three broad groups were detected: two consisting of CIMMYT lines and a mixed group consisting of both CIMMYT and IITA inbred lines. The STRUCTURE analysis revealed six subpopulations (fixation index value = 0.58), which depicts a moderate genetic diversity among the materials. Population 2 comprises the highest number of genotypes (102) from both programs. More than 89% of the elite lines had homozygosity exceeding 95%, with the remaining lines requiring further inbreeding through repeated self‐pollination. There was inconsistency in the predetermined heterotic groups' alignment between CIMMYT and IITA elite inbred lines. Analysis of molecular variance revealed that 96% of the total variation was accounted for by differences within groups, with the remaining 4% representing the variation between groups. This suggests that the two programs can benefit from germplasm exchange for the improvement of maize productivity.

Dynamic Validation of Calibration Accuracy and Structural Robustness of a Multi-Sensor Mobile Robot.

For mobile robots, the high-precision integrated calibration and structural robustness of multi-sensor systems are important prerequisites for ensuring healthy operations in the later stage. Currently, there is no well-established validation method for the calibration accuracy and structural robustness of multi-sensor systems, especially for dynamic traveling situations. This paper presents a novel validation method for the calibration accuracy and structural robustness of a multi-sensor mobile robot. The method employs a ground-object-air cooperation mechanism, termed the "ground surface simulation field (GSSF)-mobile robot -photoelectric transmitter station (PTS)". Firstly, a static high-precision GSSF is established with the true north datum as a unified reference. Secondly, a rotatable synchronous tracking system (PTS) is assembled to conduct real-time pose measurements for a mobile vehicle. The relationship between each sensor and the vehicle body is utilized to measure the dynamic pose of each sensor. Finally, the calibration accuracy and structural robustness of the sensors are dynamically evaluated. In this context, epipolar line alignment is employed to assess the accuracy of the evaluation of relative orientation calibration of binocular cameras. Point cloud projection and superposition are utilized to realize the evaluation of absolute calibration accuracy and structural robustness of individual sensors, including the navigation camera (Navcam), hazard avoidance camera (Hazcam), multispectral camera, time-of-flight depth camera (TOF), and light detection and ranging (LiDAR), with respect to the vehicle body. The experimental results demonstrate that the proposed method offers a reliable means of dynamic validation for the testing phase of a mobile robot.

Exploration of mathematical concepts in Batik Truntum Surakarta

This research investigates the mathematical concepts embedded within Batik Truntum motifs, including geometry, analysis, arithmetic, and algebra. Employing a qualitative methodology with an ethnographic approach, the study addresses four critical questions: "Where should I begin the search?", "How do I locate the concepts?", "How do I identify significant findings?", and "How do I comprehend these findings?". Through addressing these questions, the researcher successfully analyzed the mathematical concepts inherent in Batik Truntum. Of the four primary mathematical concepts, only geometry was substantiated by experts, encompassing sub-concepts such as geometric transformations, line relationships, and planar geometry. Specifically, transformation geometry includes translation and reflection, while the study of line relationships involves line alignment, and planar geometry covers the topic of circles. This research aims to ensure that the millennial generation remains connected to batik as a vital part of Indonesia's cultural heritage, preventing cultural erosion amidst technological advancements through the intricate and exploratory study of mathematics.

Geological Disaster Susceptibility Evaluation Using Machine Learning: A Case Study of the Atal Tunnel in Tibetan Plateau

Tunnels serve as vital arteries in the realm of transportation and infrastructure, facilitating the seamless flow of movement across challenging terrains. With the increasing demand experienced by the traffic network on the Tibetan Plateau, deep-buried, lengthy tunnels have become one of the extremely important types of roads for local residents to pass through. Geological disaster susceptibility mapping by hybrid models has been proven to be an effective means to reduce the losses caused by disasters in a large area. However, there has been relatively little research conducted in tunnel areas with significant human activity. To explore the feasibility of conducting geological disaster susceptibility assessment in tunnel areas, we chose the Atal Tunnel as a study project; as a strategic passageway, this exemplifies the significant geological hurdles encountered on the Tibetan Plateau. Employing multi-source remote sensing data, we meticulously mapped the distribution of geological disasters and identified nine environmental and geological variables pivotal for susceptibility evaluation. We harnessed interpretable ensemble learning models to assess this susceptibility, comparing the efficacy of four distinct models: the weight of evidence method (WoE), the frequency ratio (FR), logistic regression (LR) and the support vector machine (SVM). The precision of our findings was rigorously tested using metrics such as the percentage of disaster area encompassed within each risk level, the Area Under the Curve (AUC) value, and the Receiver Operating Characteristic (ROC) curve, and all results were highly accurate. Notably, the WoE-LR model achieved superior performance, boasting an impressive accuracy rate of 90.7%. Through model interpretation, we discerned that the alignment of the road line is the most critical determinant in the evaluation of tunnel geological disaster susceptibility, underscoring the high precision of our model. The extension and successful application of this research in plateau areas hold profound implications for sustainable development. Moreover, the practical application of these research findings will provide a practical reference for the design and construction of projects in similar plateau areas, with positive outcomes that extend well beyond the immediate geographical area of the projects.

Robotic-assisted medial unicompartmental knee arthroplasty restored prearthritic alignment and led to superior functional outcomes compared with conventional techniques.

Robotic-assisted medial unicompartmental knee arthroplasty (UKA) can ensure precise preoperative planning, minimise soft tissue damage and restore native coronal alignment. However, few studies have investigated how these advantages translate into differences in early postoperative outcomes. This study aimed to compare differences in early outcomes between conventional UKA (C-UKA) and robotic-assisted UKA (R-UKA). This retrospective study investigated two groups of patients who underwent medial UKA: C-UKA group (n = 35) and R-UKA group (n = 35). We assessed (1) serum indicators (hemoglobin, creatine kinase and C-reactive protein) and pain visual analogue scale (VAS) at postoperative days (PODs) 1, 2, 4 and 6; (2) radiologic parameters including joint line height change and arithmetic and mechanical hip-knee-ankle angle (aHKA and mHKA); (3) patient-reported outcomes including Knee Society Scores, Western Ontario and Mcmaster Universities Arthritis Index (WOMAC) and Forgotten Joint Score-12 (FJS-12) at 1-year follow-up. Despite similar serum indicator results, pain VAS was lower in the R-UKA group than in the C-UKA group at PODs 2 (2.5 ± 1.3 vs. 3.6 ± 1.2, p = 0.02), 4 (2.4 ± 0.9 vs. 3.3 ± 1.0, p = 0.03) and 6 (1.9 ± 1.1 vs. 3.1 ± 1.1, p < 0.01). The joint line height change was significantly lower in the R-UKA group than in the C-UKA group (0.9 mm ± 0.6 mm vs. 2.0 mm ± 1.3 mm, p = 0.02). The equivalence test for preoperative aHKA and postoperative mHKA revealed equivalence in only the R-UKA group (p < 0.01). The R-UKA group showed better WOMAC and FJS-12 compared to C-UKA group at 1-year follow-up. R-UKA led to lower pain VAS in the early postoperative period compared with C-UKA. Additionally, R-UKA effectively restored the joint line and prearthritic lower limb alignment, resulting in superior functional outcomes at 1-year follow-up compared with C-UKA. Level III.

Template-Confined Oriented Perovskite Nanowire Arrays Enable Polarization Detection and Imaging.

Polarized light detection can effectively identify the difference between the polarization information on the target and the background, which is of great significance for detection in complex natural environments and/or extreme weather. Generally, polarized light detection inevitably relies on anisotropic structures of photodetector devices, while organic-inorganic hybrid perovskites are ideal for anisotropic patterning due to their simple and efficient preparation by solution method. Compared to patterned thin films, patterned arrays of aligned one-dimensional (1D) perovskite nanowires (PNWAs) have fewer grain boundaries and lower defect densities, making them well suited for high-performance polarization-sensitive photodetectors. Here, we fabricated PNWAs crystallographically aligned with variable line widths and alignment densities employing CD-ROM and DVD-ROM grating pattern template-confined growth (TCG) methods. The photodetectors constructed from MAPbI3 PNWAs achieved responsivity of 35.01 A/W, detectivity of 6.85 × 1013 Jones, and fast response with a rise time of 172 μs and fall time of 114 μs. They were successfully applied to high-performance polarization detection with a polarization ratio of 1.81, potentially applicable in polarized light detection systems.

Successful medial unicompartmental knee arthroplasty-What are the most important surgical tricks?

Unicompartmental knee arthroplasty (UKA) is an established surgical treatment option for end-stage anteromedial osteoarthritis with excellent functional outcomes and implant survival. Routine preoperative varus and valgus stress views are crucial for the selection of patients for unicompartmental or total knee arthroplasty. UKA is asoft-tissue based operation that aims to reconstruct the individual joint line and pre-arthritic alignment by restoring the physiological tension of the medial collateral and the cruciate ligaments. Current data for medial UKA show excellent results for both mobile and fixed bearing implant designs with the correct indication and surgical technique. Cementless fixation offers potential advantages over cemented implants. Registry data demonstrate that institutions and surgeons specializing in partial knee replacement (> 30cases/year per surgeon, > 100/year per institution) with ahigh percentage of UKA relative to the total number of knee implants (> 20%) have significantly lower revision rates.

Alignment of substance use community benefit prioritization and service lines in US hospitals: a cross-sectional study

BackgroundNon-profit hospitals in the U.S. are required by the 2010 Patient Protection and Affordable Care Act (ACA) to conduct a community health needs assessment (CHNA) every three years and to formulate an implementation strategy in response to those needs. Hospitals often identify substance use as a need relevant to their communities in their CHNAs and then must determine whether to create strategies to address such a need within their implementation strategies. The aim of this study is to assess the relationship between a hospital’s prioritization of substance use within its community benefit documents and its substance use service offerings, while considering other hospital and community characteristics.MethodsThis study of a national sample of U.S. hospitals utilizes data collected from publicly available CHNAs and implementation strategies produced by hospitals from 2018 to 2021. This cross-sectional study employs descriptive statistics and multivariable analysis to assess relationships between prioritization of substance use on hospital implementation strategies and the services offered by hospitals, with consideration of community and hospital characteristics. Hospital CHNA and strategy documents were collected and then coded to identify whether the substance use needs were prioritized by the hospital. The collected data were incorporated into a data set with secondary data sourced from the 2021 AHA Annual Survey.ResultsMultivariable analysis found a significant and positive relationship between the prioritization of substance use as a community need on a hospital’s implementation strategy and the number of the services included in this analysis offered by the hospital. Significant and positive relationships were also identified for five service categories and for hospital size.ConclusionsThe availability of service offerings is related both to a hospital’s prioritization of substance use and to its size, indicating that these factors are likely inter-related regarding a hospital’s sense of its ability to address substance use as a community need. Policymakers should consider why a hospital may not prioritize a need that is prevalent within their community; e.g., whether the organization believes it lacks resources to take such steps. This study also highlights the value of the assessment and implementation strategy process as a way for hospitals to engage with community needs.

Analysis of correlation between medial joint line change and lower limb coronal alignment after Oxford unicompartmental knee arthroplasty

Lower limb coronal alignment was thought to be a predictive factor for Unicompartmental Knee Arthroplasty (UKA) result. The tibial bony resection and implant position lead to joint line change postoperatively. Analysis was done to find out the correlation between these factors. From 2019 to 2021, 90 medial Oxford UKA were implanted by a single surgeon. Hip Knee Ankle Angle (HKAA), Lateral Distal Femoral Angle (LDFA), Medial Proximal Tibial Angle (MPTA), and intraoperative bony resection thickness were measured. The medial joint line change was calculated. The correlation between joint line change and alignment change was evaluated. The mean tibial resection thickness was 4.3 mm. The mean tibial joint line was elevated by 2.3 mm, while the mean femoral joint line proximalized by 0.8 mm. HKAA changed from 8.4° varus preoperatively to 3.6° varus postoperatively. LDFA changed from 89.0° to 86.7°. MPTA changed from 85.6° to 86.6°. Preoperative HKAA showed a strong correlation with postoperative HKAA (p < 0.001), and preoperative MPTA showed a positive correlation with postoperative HKAA (p < 0.001). While preoperative LDFA had a negative correlation with postoperative HKAA (p < 0.001). The femoral joint line change and LDFA change had a significant correlation with HKAA change (p < 0.05). The change of joint line had no correlation with postoperative HKAA in Oxford UKA. Preoperative HKAA strongly correlated with postoperative HKAA; while preoperative smaller LDFA and larger MPTA had a moderate correlation with postoperative HKAA. The femoral joint line change and LDFA change had a weak to moderate correlation with HKAA change.

Coronal alignment in normal individuals and moderate scoliosis: Normative values, variation with age and comparison with sagittal alignment

IntroductionGlobal coronal alignment is mainly assessed by C7 plumbline and central sacral vertical line (CSVL), pelvic obliquity and shoulder alignment. A detailed analysis is mandatory when treating spinal deformity. It remains unclear to what extent mild scoliosis influences global coronal alignment. Research questionThe objective was to define a comprehensive set of coronal alignment parameters and to investigate differences between individuals without spinal deformity and with mild scoliosis. The relationship between coronal and sagittal alignment and the influence of age were studied. MethodsRadiographs of 236 normal individuals (Group N) and 140 patients with scoliosis <35° (Group S) were prospectively collected. Coronal parameters were femoral head distance and angle, pelvic obliquity, Maloney angle, L4 and L5 inclinations, coronal T1 pelvic angle, C7-CSVL and odontoid CSVL offset, coracoid distance and angle. Sagittal cervical, spinopelvic, thoracolumbar and global parameters were measured. ResultsThere was no significant difference between groups N and S for coronal parameters, except for L4 and L5 inclinations with a mean difference of 3,3° (p < 0,001). Global coronal alignment kept constant throughout age groups in N and S groups. Sagittal parameters varied with age: C2-C7 lordosis (p < 0,001), T1-T12 kyphosis (p < 0,001), pelvic incidence (p < 0,001). There was no correlation between global coronal and sagittal alignment: R-values ranging from −0.2 to 0.2. ConclusionGlobal coronal parameters were comparable in normal individuals and in scoliosis <35°. Coronal plane parameters were not influenced by age. Sagittal plane parameters varied significantly with age. There was no direct link between coronal et sagittal alignment.

Short-term effectiveness of ultrasound-guided Kirschner wire provocation technique in treatment of Salter-Harris types Ⅰ and Ⅱ periosteal entrapment of distal tibial epiphyseal fractures in children and adolescents

To investigate the short-term effectiveness of ultrasound-guided closed reduction by Kirschner wire provocation technique in the treatment of Salter-Harris types Ⅰ and Ⅱ periosteal entrapment of distal tibial epiphyseal fractures in children and adolescents. Between May 2019 and May 2022, 41 patients with Salter Harris types Ⅰ and Ⅱ distal tibial epiphyseal fractures were admitted, all of whom had periosteal entrapment on preoperative MRI, and 38 cases (92.7%) were confirmed to have periosteal entrapment by intraoperative ultrasound. There were 24 males and 14 females, the age ranged from 6.8 to 15.7 years, with an average of 10.7 years; and there were 20 cases of Salter Harris type Ⅰ and 18 cases of type Ⅱ. The time from injury to operation was 22-76 hours, with an average of 28.4 hours. The preoperative imaging examination showed excellent alignment in 4 cases, good in 20 cases, and poor in 14 cases. The ultrasound guided Kirschner wire provocation technique for closed reduction and percutaneous Kirschner wire internal fixation were performed. The operation time, intraoperative fluoroscopy frequency, fracture healing time, and complications were recorded. Anteroposterior and lateral X-ray films of the affected ankle joint were taken before operation, at 3 months after operation, and at last follow-up to observe the healing of the fracture, and anteroposterior X-ray films of the whole length of both lower limbs were taken to evaluate the alignment of the force lines of the affected limbs. The range of motion (ROM), visual analogue scale (VAS) score, and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score were used to evaluate ankle function. The mechanical lateral distal tibia angle (mLDTA) and the anatomic anterior distal tibia angle (aADTA) were measured. The operation time ranged from 17 to 52 minutes, with an average of 22.6 minutes, and the intraoperative fluoroscopy frequency ranged from 3 to 11 times, with an average of 4.2 times. X-ray examination during operation and at 2 days after operation showed that anatomical reduction was achieved. All patients were followed up 10-24 months, with an average of 16.4 months. All fractures healed in 6.1-7.2 weeks, with an average of 6.3 weeks; no fracture displacement occurred, and the patients recovered to their pre-injury level of motion at 6 months after operation. Needle tail irritation occurred in 2 cases at 4 weeks after operation, and they recovered after symptomatic treatment. During the follow-up, there was no serious complication such as incision deep infection, bone nonunion, delayed union, and malunion. At last follow-up, the patients' alignment were all excellent, and the difference was significant when compared with preoperative one ( Z=-7.471, P<0.001). The VAS score, AOFAS ankle-hindfoot score, dorsiflexion-plantar flexion ROM, varus-valgus ROM, mLDTA, and aADTA significantly improved at 3 months after operation and last follow-up when compared with preoperative ones ( P<0.05). Ultrasound-guided closed reduction by Kirschner wire provocation technique for treating Salter-Harris types Ⅰ and Ⅱ periosteal entrapment of distal tibial epiphyseal fractures in children and adolescents is minimally invasive and safe.

Laxity, Balance, and Alignment of a Simulated Kinematic Alignment Total Knee Arthroplasty.

Kinematic alignment (KA) and related personalized alignment strategies in total knee arthroplasty (TKA) target restoration of native joint line obliquity and alignment. In practice, deviations from exact restoration of the prearthritic joint surface are tolerated for either the femur or tibia to achieve ligamentous balance. It remains unknown what laxity, balance, and alignment would result if a pure resurfacing of both femur and tibia were performed in a KA TKA technique. We used data from 382 robot-assisted TKA performed with a digital joint tensioner to simulate TKA with a pure resurfacing KA technique for both femur and tibia. All knees had the posterior cruciate ligament retained. Knees were subdivided into 4 groups based on preoperative coronal alignment: valgus, neutral, varus, and high varus. Medial and lateral laxity in extension and flexion, balance in extension and flexion, and coronal plane alignment were compared between groups using analysis of variance testing. In simulated pure resurfacing KA TKA across a range of preoperative coronal plane deformities, only 11%-31% of knees would have mediolateral extension ligament balance within ±1 mm, and 20%-41% would have a medial flexion gap that is looser than the lateral flexion gap. Over 45% of knees would have coronal hip-knee-ankle angle >3 degrees from mechanical neutral. In simulations of pure resurfacing KA TKA, there was wide variability in the resulting laxity and alignment outcomes. Most knees had alignment and balance outcomes outside of normally accepted ranges. Techniques that deviate from pure resurfacing in order to achieve balance appear favorable.

Study Case of Marine Propulsion Shaft Measurements by the Strain Gage Method: before and after a ship hull grounding accident

The strain gage method for propulsion shaft bending moment verificationhas been in use since the 80’s. In this work, the authors present theirprocedure and results of this method to an Anchor Handling Tug Supply(AHTS) ship. The method was applied in this ship in two occasions: afterdelivery in 2018 and after a grounding accident in 2019. After a period ofhull repair, the bearing reactions were verified at the same time by Jackupand Strain Gage methods. The results by the Strain Gage techniqueare considered more accurate and complete than those of the Jack-up.Based on the Strain Gage results, it was concluded that the groundingaccident caused a change in the alignment of the shaft lines, mainly onstarboard side. The comparison between the methods presented thesame graphic shape, however the Jack-up measurements differed fromthe Strain Gage ones at some points due to some factors noted anddiscussed by the authors.

An Object SLAM Framework for Association, Mapping, and High-Level Tasks

Object SLAM is considered increasingly significant for robot high-level perception and decision-making. Existing studies fall short in terms of data association, object representation, and semantic mapping and frequently rely on additional assumptions, limiting their performance. In this paper, we present a comprehensive object SLAM framework that focuses on object-based perception and object-oriented robot tasks. First, we propose an ensemble data association approach for associating objects in complicated conditions by incorporating parametric and nonparametric statistic testing. In addition, we suggest an outlier-robust centroid and scale estimation algorithm for modeling objects based on the iForest and line alignment. Then a lightweight and object-oriented map is represented by estimated general object models. Taking into consideration the semantic invariance of objects, we convert the object map to a topological map to provide semantic descriptors to enable multi-map matching. Finally, we suggest an object-driven active exploration strategy to achieve autonomous mapping in the grasping scenario. A range of public datasets and real-world results in mapping, augmented reality, scene matching, relocalization, and robotic manipulation have been used to evaluate the proposed object SLAM framework for its efficient performance.

Alignment of Substance Use Community Benefit Prioritization and Service Lines in US Hospitals

Alignment of Substance Use Community Benefit Prioritization and Service Lines in US Hospitals

Measurements of beam characteristics on a 70 MeV H− cyclotron system for ISOL beam production

A 70 MeV H− cyclotron system was commissioned in order to measure the beam characteristics for the isotope separation on line (ISOL) operation in the energies range between 40 and 70 MeV. Using internal beams, the cyclotron magnet was precisely isochronized by applying the Smith-Garren method, achieving a main-coil current margin of 0.2 A for the beam stability. In the center region, beam profiles were measured by a differential radial probe to verify the specified dee voltage of 50 kV, which allows well-defined turn separation. Extracted beams were then used to check the beam line alignment by monitoring beam losses on segmented collimators and measuring variations on beam profiles. We measured transverse emittances of the cyclotron beam at a current of 25 µA by observing the beam profiles with upstream quadrupole strengths varied, which was the first time for this kind of 70 MeV cyclotron. Transmission efficiency along the beam line was measured as above 98% at a current of 100 µA. A temporary beam line was installed in the ISOL area, and we measured beam current distributions using a beam profile monitor shaped by wobbling at 60 Hz at a target location for beam diameters of 2 and 5 cm. A specific current distribution is generally required to reduce the maximum thermal stresses induced on the target. Finally, a maximum beam power of 50 kW was successfully tested at 70 MeV for 6 h.

Case study on the shaft line alignment for a 180 000 tdw bulk carrier vessel

Alignment means the determination of displacements and breaks between two shafts and their elimination so that the geometric axes of the shafts become approximately collinear, and the deviations are within the permissible limits. This paper presents the methodological steps of the shaft line alignment (as a case study for a bulk carrier vessel of 180 000 tdw) through two classic approaches: with the help of a ruler and feeler gauge (templet) respectively with the help of dial gauge. Comparative analysis of the performances of the two methods, can provide essential information to an engineer in choosing the optimal option for alignment of the shaft lines both in the case of vessels in service and, mainly, in the case of new building’s. The originality of the work consists in carrying out the detailed calculations for displacements and breaks, with the graphical highlighting of the calculated values in the limit allowed intervals. Also, for each method are presented and commented the advantages and disadvantages.

Learning curve and short-term clinical outcomes of a new seven-axis robot-assisted total knee arthroplasty system: a propensity score-matched retrospective cohort study

ObjectiveThe purpose of the present study was to determine the learning curve for a novel seven-axis robot-assisted (RA) total knee arthroplasty (TKA) system and to explore whether it could provide superior short-term clinical and radiological outcomes compared with conventional surgery.MethodsIn the present retrospective study, 90 patients who underwent RA-TKA were included in robot-assisted system (RAS) group and 90 patients who underwent conventional TKA were included in the conventional group. The duration of surgery and robot-related complications were recorded to evaluate the learning curve through cumulative sum and risk-adjusted cumulative sum methods. The demographic data, preoperative clinical data, preoperative imaging data, duration of surgery, alignment of the prosthesis, lower limb force line alignment, Knee Society score, 10-cm visual analog scale pain score and range of motion were compared between the RAS and conventional groups. In addition, the proficiency group was compared with the conventional group using propensity score matching.ResultsRA-TKA was associated with a learning curve of 20 cases for the duration of surgery. There was no significant difference in indicators representing the accuracy of the prosthetic installation between the learning and proficiency phases in RA-TKA group patients. A total of 49 patients in the proficiency group were matched with 49 patients from the conventional group. The number of postoperative hip–knee–ankle (HKA) angle, component femoral coronal angle (CFCA), component tibial coronal angle (CTCA), and sagittal tibial component angle (STCA) outliers in the proficiency phase was lower than that in the conventional group, while deviations of the HKA angle, CFCA, CTCA, and STCA in the proficiency phase were significantly lower than those in the conventional group (P < 0.05).ConclusionIn summary, from the learning curve data, 20 cases are required for a surgeon using a novel seven-axis RA-TKA system to enter the proficiency phase. In the proficiency group, compared with the conventional group using propensity score matching, the RAS was found to be superior to the conventional group in prosthesis and lower limb alignment.

Machine learning performance comparison for main propulsive shafting systems alignment

The ship shaft alignment is crucial to achieve a high-performance propulsion system. This alignment is carried out, still in drydock, by adjusting the bearings' offsets. However, there are numerous available combinations sets of vertical offsets which results in good alignment final condition. Defining an optimum set of vertical displacements is costing shipyards a valuable time. Therefore, this work proposes the use of machine learning algorithms to predict if a given set of offsets, following the mandatory rules in force, should be implemented or not. In this manner, this paper presents a case study where a finite element model of an Anchor Handling Tug Supply (AHTS) vessel’ shaft line was assembled in order to obtain the bearings reactions, shaft line deflections, shear forces, bending moments and, finally, the influence coefficients matrix (ICM). Those data were used to feed machine learning (ML) models based on four different algorithms, namely, K-Nearest-Neighbors, Extremely Randomized Trees, Random Forest and Gradient Boosting in order to solve multiclass classification problems concerning the offset's set to be applied in the alignment of the shaft line. Results showed that the Gradient Boosting and Random Forest algorithms presented the best results, achieving up to 98.1% of precision in one of the 36 scenarios tested, and an average precision above 96.0%. Such results corroborated with the authors' proposal to implement ML techniques as a way to speed up the currently very time-consuming shaft alignment process.

Analysis of Dynamic Characteristics of Low-Floor Train Passing Switch in Facing Direction with Bad Alignment Irregularity Ahead of the Turnout

A low-floor train–turnout coupling dynamic model considering bad alignment irregularity ahead of the turnout was established on the basis of a field test in which the dynamic performances of a low-floor train passing through a no. 6 turnout in a rail transit depot in China had been measured, as well as the line alignment and wheel and rail profiles. There are two types of wheelsets in the low-floor train: integral wheelset and independent wheelset. The model fully considers the coupling effect between the vehicle and the ballast components, and the simulated results are in consistence with measured results in the field test. Based on this, the influences of train speed, the wheel–rail friction coefficient, and the track alignment optimization of the dynamic performance of low-floor trains passing switch in facing direction are analyzed. The main results indicate that eliminating alignment irregularities before the switch can effectively improve the dynamic performance of the integrated wheelset in the switch and the lateral forces of the outer wheels of these two vehicles are reduced by about 80%, the derailment coefficients are reduced by about 70%, the vertical force is reduced by about 10–20% and wheel load is reduced by approximately 30%.