Alignment Design Research Articles

Environment-Aware Beam Probing Codebook Design for Two-Timescale Beam Alignment in RIS-Assisted Communication Systems

Environment-Aware Beam Probing Codebook Design for Two-Timescale Beam Alignment in RIS-Assisted Communication Systems

An Interference Alignment Design with Higher Multiplexing Gain by the Reduced Channel Extension

For a K-user Single Input Single Output fading interference channel, Cadambe and Jafar proposed a scheme that achieves K=2 multiplexing gain asymptotically employing interference alignment technique. This scheme is improved by Choi et al. in which for reduced channel extension, higher multiplexing gain is achievable. But the existing designs require an infinite number of channel extension to achieve the upperbound. Our proposed design attains higher multiplexing gain that is arbitrarily close to the upper-bound by using a lot lower number of channel extension in comparison with the other existing interference alignment schemes. On the other hand, due to the great symbol extension reduction of the channel, the computational complexity to achieve K=2 degrees of freedom (desired upper-bound) is also reduced significantly. Moreover, it can be shown that the proposed design achieves higher interference alignment quality. For a limited channel extension, the proposed scheme leads to a better allocation of the signal space at each receiver to the desired and interfered signal. This results to a higher quality of alignment.

Two-axial alignment mirror for optical-quantum generator resonator (Tomsk)

There are currently laser systems used at many stages of construction. They allow to solve engineering problems with great accuracy. The paper considers the design of a twoaxis alignment unit.Purpose: The aim of this work is to design the two-axial alignment mirror of the optical quantum oscillator resonator.Methodology: Deformation of elastic elements are determined by the energy method. The relation between rotation angles of the alignment screw and the resonator mirror normal is determined analytically.Research findings: The influence of design parameters of the assembly on its performance is evaluated. A comparative analysis is presented for the sensitivity of two-axial and uniaxial knots of the alignment mirror. The advantage of the two-axial knot is shown by calculations. The obtained results can be applied in laser construction technology.

Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material)

ObjectivesTo conduct a physiochemical and mechanical material analysis on 3D printed shape-memory aligners in comparison to thermoformed aligners. Materials and methodsFour materials were examined, including three thermoformed materials: CA Pro (CP), Zendura A (ZA), Zendura FLX (ZF), and one 3D printed material: Tera Harz (TC-85). Rectangular strips measuring 50 × 10 × 0.5 mm were produced from each material. Five tests were conducted, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), shape recovery tests, three-points bending (3 PB), and Vickers surface microhardness (VH). ResultsDSC recorded glass transition temperatures (Tg) at 79.9 °C for CP, 92.2 °C for ZA, 107.1 °C for ZF, and 42.3 °C for TC-85. In DMA analysis at 20–45 °C, a prominent decrease in storage modulus was observed, exclusively for TC-85, as the temperature increased. Notably, within the temperature range of 30–45 °C, TC-85 exhibited substantial shape recovery after 10 min, reaching up to 86.1 %, while thermoformed materials showed minimal recovery (1.5–2.9 %). In 3 PB test (at 30, 37, 45 °C), ZA demonstrated the highest force at 2 mm bending, while TC-85 exhibited the lowest. Regarding VH at room temperature, there was a significant decrease for both ZA and ZF after thermoforming. ZA had the highest hardness, followed by ZF and TC-85, with CP showing the lowest values. ConclusionsTC-85 demonstrates exceptional shape memory at oral temperature, improving adaptation, reducing force decay, and enabling, together with its higher flexibility, extensive tooth movement per step. Additionally, it maintains microhardness similar to thermoformed sheets, ensuring the durability and effectiveness of dental aligners. Clinical relevanceThe 3D printed aligner material with shape memory characteristics (4D aligner) has revolutionized the orthodontic aligner field. It showed mechanical properties more suitable for orthodontic treatment than thermoforming materials. Additionally, it offers enhanced control over aligner design and thickness, while optimizing the overall workflow. It also minimizes material wastage, and reduces production expenses.

Development of stimuli-responsive flexible micropillar composites via magneto-induced injection molding and characterization of magnetic particle alignment

Magnetic soft composites have emerged as a promising soft actuator with a high degree of precision in the magnetic field stimuli system. But, their mass manufacturing strategies have yet to be developed, and most studies focus on small-scale near-net shaping production. Here, we first apply injection molding (which only takes a few seconds to shape) to fabricate the stimuli-responsive flexible micropillar composites with magnetic particle alignment design using an external magnetic field. The arrays exhibit magnetically anisotropic particle alignment up to 82.57 % along the longitudinal direction, showing a magnetic bending actuation response. We achieve a structural novelty of the magnetic micropillar with a high aspect ratio of up to 10 and pattern sizes of 50 μm via sacrificial LIGA insert mold and magneto-induced injection molding. For advanced mass production, the permanent metal mold is also applied to develop the micropillar composites based on the mechanical demolding approach; successful manufacturing is achieved by fabricating defect-free micropillar with 200 μm cylindrical pattern size and aspect ratio of 6. Further, the effect of powder volume fraction on the magneto-rheological behavior and corresponding magnetic performance is characterized in the injection molding process. The magnetic particle alignment trend is confirmed by the torque balance and the criteria of critical solids loading. Finally, we establish an injection molding process for magnetic soft composites, and verify the optimal powder fraction for the particle alignment.

Modeling and application of a customized knowledge graph for railway alignment optimization

Railway alignment optimization is a complex process in which human knowledge and experience are extensively used. However, the related knowledge is usually unstructured, which is difficult for computers to recognize. Moreover, related knowledge is applied in fragmented ways in existing alignment optimization methods, which are thus difficult to update with actual advancements of human experience and knowledge. To solve the above problems, the first-known knowledge graph modeling method for railway alignment optimization is proposed in this paper. First, a hierarchical and categorized semantic network modeling approach for railway alignment design knowledge is devised. Based on this, a railway alignment design knowledge graph (RAD-KG) is constructed. Then, a rapid knowledge retrieval method is proposed for improving the querying efficiency from the RAD-KG during alignment optimization. Finally, the RAD-KG integrating multiple alignment design principles is successfully applied to a real-world case. It is verified that the alignment generated by the proposed method reduces costs by 9.2% compared with conventional manual work by experienced engineers. Moreover, the RAD-KG-assisted method can rapidly update alignment design guidelines during optimization and, hence, produce several alignment alternatives satisfying various complicated requirements, which confirms the flexibility of the proposed method.

A 3D Monte Carlo tree search method for railway alignment optimization

Railway alignment design is an important process, which fundamentally affects the construction, operation and maintenance of a railway. However, optimizing an alignment is challenging due to, e.g., the usually huge search space, infinite number of possible alternatives and numerous constraints. To address this problem, we propose a three-dimensional Monte Carlo Tree Search (3D-MCTS) method for alignment optimization. Specifically, a time-varying selection approach is first designed for efficiently exploring the search space. Then, the feasible search space is dynamically delineated with a customized tree expansion operator to accelerate the search process. In addition, a simulation strategy with global reward estimation is proposed to balance global exploration and local exploitation during optimization, which contributes to enhancing the quality of the optimized alignment. Finally, the proposed 3D-MCTS is applied to a complex real-world railway case. It shows that the 3D-MCTS can find better solutions compared to the best alignments that are manually designed by experienced engineers or produced by a previous distance transform algorithm. Two sensitivity analyses also reveal the 3D-MCTS's performance and robustness with respect to cost optimization and search efficiency.

Synthetic Drivers’ Performance Measures Related to Vehicle Dynamics to Control Road Safety in Curves

The road alignment design relies on the knowledge of vehicle dynamics variables. However, it assumes that drivers faithfully follow the lane axis on straights and curves. Deviating from this assumption leads to unexpected outcomes and can significantly impact users’ safety. In this context, vehicle speed and longitudinal acceleration play a crucial role as key references in the international standards. They provide insights into critical driving aspects; therefore, it is essential to thoroughly analyze their real trends. Broad data collection campaigns should derive synthetic indicators in order to highlight eventual significant deviations between the ideal and real dynamics. To achieve this objective, the authors propose some indexes deduced during an experimental study with a Sim-Easy driving simulator, by AVSimulation. Importantly, these indicators can be freely applied in real driving scenarios without limitations. These indexes were tested on four different horizontal curves and proved effective in identifying relevant characteristics related to longitudinal acceleration and speed. Looking ahead, by analyzing similar data for numerous driving contexts on real roads, infrastructure managers could use this methodology to identify those sections with increased vulnerability for users’ safety. Moreover, the collected data from sensors, processed using these indicators, can be filtered and transmitted to users (via ADAS tools) while driving on a specific road to provide timely warnings about potential difficulties. The indicators control the physical variable (acceleration or speed) on a certain geometric element with reference to what is prescribed by the standard. For example, the acceleration indicators are normalized with respect to a threshold value while for speed indexes, the result depends on the difference between the end control points of the geometrical element. In both cases, international regulations report prescribed or recommended reference values, so the analyst is immediately aware of any critical issues in the maneuver.

BIM-centered high-speed railway line design for full infrastructure lifecycle

In the field of civil engineering, specifically within railway projects, the adoption of Building Information Modeling (BIM) has become imperative. However, the sector's adherence to traditional methods for infrastructure design and management has delayed the widespread adoption of BIM. This paper describes a BIM-centered methodology applied to a real-world High-Speed Railway Line (HSRL) project. Through an extensive examination of HSRL design parameters and the integration of various BIM-based tools, a 3D parametric design model is generated. This model serves as the foundation for evaluating up to five design alternatives, considering technical and economic aspects. Furthermore, a degradation model is proposed to assess alternative performance over the infrastructure's full lifecycle under specific rail traffic assumptions. This facilitates a rapid evaluation of alignment design's impact on maintenance costs. The paper draws two main conclusions with potential benefits for both private companies and railway administrations: Firstly, BIM proves feasible and advantageous despite some interoperability challenges, highlighting the need for continued advancements in BIM software compatibility. Secondly, the proposed approach can potentially lead to up to 40% cost savings in maintenance for railway administrations.

All-knitted stretchable dipole antenna: design, fabrication, and effects of yarn alignments on antenna electromagnetic and tensile properties

With the evolution of the Internet of Things, stretchable antennas are playing an increasingly important role in wearable devices and flexible electronics. Typical drawbacks of current stretchable antennas are complex manufacturing processes, inadequate ventilation, and limited flexibility, which negatively impact their comfort and practicality. In this study, an all-knitted stretchable dipole antenna was designed and fabricated. This antenna was breathable and flexible like regular knitted fabric and had a simple manufacturing process. In addition, the effects of two yarn alignment types, namely antenna arms aligned in the course (AaC) and wale (AaW) directions, on antenna electromagnetic properties under tensile stress were investigated. Under unstretched conditions, both antenna AaC and AaW exhibited S11 of less than –10 dB at the operating frequency of 915 MHz, demonstrating good impedance matching performance and omnidirectional radiation characteristics. When stretched along the arm length direction, the frequency variations and strain of antenna AaC and AaW displayed strong linear relationships. Specifically, antenna AaC exhibited a higher sensitivity to the resonant frequency variation induced by strain when compared to antenna AaW. The results suggest that the antenna AaC are a more desirable option to be used as a sensor for human body movement monitoring. This study provides the theoretical basis and experimental foundation for the design and large-scale production of stretchable antennas utilizing textile materials.

Improvements in the Horizontal Alignment and Vertical Profile of Balampur Ghat Section in Bhopal-Vidisha State Highway Road (SH-18) using MXRoad Software

Abstract: Geometric design of highway deals with designing of physical visible features of highway those comprise of horizontal alignment, vertical profile, circular and transition curves, superelevation, Summit and valley curves, cross sectional elements, sight distances and other features. From the safety point of view, road geometric features should be well designed as per the IRC recommendation. In this research work, the horizontal alignment and vertical profile have designed of Balampur Ghat section in the Bhopal-Vidisha Road which is in the Madhya Pradesh State of India. The objective of this research work is “Improvements in the Horizontal alignment and Vertical profile of Balampur Ghat Section in Bhopal-Vidisha State Highway Road (SH-18) using MX Road Software”. The design of horizontal alignment and vertical profile have been done for Balampur ghat section approx. 2.0 km in length of State highway no. 18 (SH-18) of Madhya Pradesh. SH-18 is connected to Vidisha from Bhopal in the state of Madhya Pradesh and having heavy commercial traffic. Balampur ghat section is hilly terrain and have two improper horizontal curves along with 6.5% of vertical gradient and because of this reason that section is not safe for deriving therefore it has become an accident-prone area and the accident-prone area have the human and economical losses so it should be improved and re design of the horizontal and vertical alignment for safe design speed. The proposed methodology is on the basis of inventory survey (preliminary survey), topographic survey and MX Road software. In inventory survey take the data of existing road and find the suitable route of alternative alignment if re-alignment is required in the road. Then the topographic survey done on the existing road and alternative alignment. Import the topographic data of the road in MX Road software for generate existing surface of the road for design of horizontal alignment and vertical profile. As per IRC recommendations, there are two alternative alignments designed of the existing ghat section. As per the outputs of this research work, the length of both improved alignments is short as compare to existing road. There are no improper curves at improved alignment and maximum gradient is 4.2% which is less than the existing gradient (6.5%). The minimum design speed is 40-50 kmph which was 20 kmph in existing road. The both two improved alignments are safer as compare to existing alignment and the design speed of the vehicle has been increased. The improved alignment 2 is straighter than the improved alignment The improved alignment has also reduced the human and economic losses.

The Role of Cloud Computing on Accounting Information System Quality:A Study in Hotel Industry

The hotel industry is a significant sector for Indonesian economic growth. Nowadays, cloud computing is bringing much potential for hotels to increase their competitive advantage, specifically in facilitating Information Systems (IS). However, we found still limited study that investigates cloud-based IS in accounting functions. Therefore, this study aims to analyze 1) the impact of the human aspect in determining cloud performance, 2) the impact of cloud performance on the relative advantage and compatibility of cloud-based Accounting Information Systems (AIS) in the hotel industry, and 3) the impact of its relative advantage and compatibility on cloud-based AIS quality. Using purposive sampling, the data was collected from accounting and/or information manager hotels in North Sumatra, Indonesia. The collected data were analyzed using variance-based Structural Equation Modeling (SEM). We found that human, cloud performance, and technology adaptability are the critical antecedents of cloud-based AIS quality in the hotel industry. Hotel leaders should consider user computer-self efficacy and cloud-AIS alignment design while developing and integrating cloud-based AIS into their general system.

Transfer Alignment Design Using a Gyro-free Inertial Navigation System

Transfer Alignment Design Using a Gyro-free Inertial Navigation System

Multi-scale alignment in highly piezoelectric polyacrylonitrile nanofibers separator for advanced self-charging supercapacitor

Self-charging supercapacitor (SCSPC) is an integrated device that can convert mechanical energy into electrical energy and store it to power microelectronics without need a rectifier for DC conversion. Here, we report a multi-alignment design idea for polyacrylonitrile (PAN) piezoelectric nanofiber instead of traditional polyvinylidene fluoride (PVDF) as a separator in SCSPCs, which greatly improves device self-charging performance and index. The combination of synergistic effect of polarization and the stretching process in electrospinning technology can achieve PAN nanofibers orderly arrangement at macroscopic level and alignment of conformation and cyano groups at microstructural level, resulting in excellent hydrophilicity (contact angle 0 °), high piezoelectric property (3.80 μW at a load resistance of 1 MΩ), high mechanical property (7.77 MPa), and outstanding cycling stability (unchanged after 22,000 cycles). As a result, the SCSPCs based on PAN piezoelectric separator has a high conversion efficiency of 12.53%, an energy density of 37.60 mJ cm−2 at power density of 1.01 mW cm−2, and a capacitance retention 91.7% after 5000 compressive cycles. The SCSPC@PAN with working area of 4 × 4 cm2 was attached on elbow, shoes, and bicycle tire to collect biomechanical energy and covert mechanical energy into electrical energy and store. Two SCSPC@PAN in series attached on one shoe can light 3.0 V LEDs after working for 40 min. This multi-scale alignment design idea and understanding the relationship between structure of PAN piezoelectric membrane and properties of SCSPC@PAN would provide important basis for design advanced piezoelectric separator for SCSPCs.

Analysis of Visual Load on Curve and Longitudinal Slope Combination of Extra-Long Underwater Tunnel Based on Visual Sensitive Region

Extra-long underwater tunnels are important traffic nodes in urban road networks and have a high incidence of traffic accidents. The frequent occurrence of curve and longitudinal slope combinations in such tunnels increases crash risk and has a negative impact on traffic safety. Vision is the most important way to obtain traffic information, and visual load is a good measure of driving risk. To explore the impact of curve and longitudinal slope combinations on a driver’s visual load in an extra-long underwater tunnel, eye-movement data and speed data were obtained through a vehicle experiment. Based on driver gaze distribution, the area and location of the visual sensitive region are calculated, and a model of the relationship between the region’s stability and the curve and longitudinal slope at different speeds is established, and applied to the visual-load evaluation. The results show that the curve or longitudinal slope has a significant influence on vehicle speed. High-visual-load areas are mainly located in small-radius curve and large longitudinal slope combination areas and extremely small-radius curve areas. For example, for a combination of left-turn curve and longitudinal slope with a speed of 50–60 km/h, when the curve radius is less than 1150 m and the longitudinal slope is less than −2.4%, or the curve radius is less than 1100 m and the longitudinal slope is greater than 2.2%, the visual load is high and driving safety is poor. This study can provide a theoretical basis for tunnel alignment design and safe operation.

Characteristics, numerical analysis and countermeasures of mud inrush geohazards of Mountain tunnel in karst region

The excavation of tunnels in karstic rocks inevitably intersects with karst caves even with reasonable geological survey and alignment design. The filler in karst caves directly affect the harmfulness of mud inrush geohazards to tunnels. Therefore, it is essential to understand the properties and failure characteristics of the filler in karst caves before treating karst caves. Based on a tunnel mud inrush case in Guangxi Province, China, failure characteristics and mechanism of clay filler in karst cave were analyzed. Besides, geological survey and geological prospecting indicate that the clay filler was formed by the deposition of surface clay entering the karst cave from the cracks of rock mass. The failure evolution process of clay filler was demonstrated based on discrete element method. The numerical simulation results show that excavation induced sliding force and insufficient shearing strength of clay were the mainly triggering of instability of clay filler in the karst cave. Advanced grouting, construction method improving were used to prevent mud inrush from bursting again and achieved satisfactory reinforcement effect. The lessons and analysis results in this case has reference value for the prevention of tunnel mud inrush in karst area.

Effects of different designs of orthodontic clear aligners on the maxillary central incisors in the tooth extraction cases: a biomechanical study

BackgroundControlling the 3D movement of central incisors during tooth extraction cases with clear aligners is important but challenging in invisible orthodontic treatment. This study aimed to explore the biomechanical effects of central incisors in tooth extraction cases with clear aligners under different power ridge design schemes and propose appropriate advice for orthodontic clinic.MethodsA series of Finite Element models was constructed to simulate anterior teeth retraction or no retraction with different power ridge designs. These models all consisted of maxillary dentition with extracted first premolars, alveolar bone, periodontal ligaments and clear aligner. And the biomechanical effects were analysed and compared in each model.ResultsFor the model of anterior teeth retraction without power ridge and for the model of anterior teeth no retraction with a single power ridge, the central incisors exhibited crown lingual inclination and relative extrusion. For the model of anterior teeth no retraction with double power ridges, the central incisors tended to have crown labial inclination and relative intrusion. For the model of anterior tooth retraction with double power ridges, the central incisors exhibited a similar trend to the first kind of model, but as the depth of the power ridge increased, there was a gradual decrease in crown retraction value and an increase in crown extrusion value. The simulated results showed that von-Mises stress concentration was observed in the cervical and apical regions of the periodontal ligaments of the central incisors. The clear aligner connection areas of adjacent teeth and power ridge areas also exhibited von-Mises stress concentration and the addition of power ridge caused the clear aligner to spread out on the labial and lingual sides.ConclusionsThe central incisors are prone to losing torque and extruding in tooth extraction cases. Double power ridges have a certain root torque effect when there are no auxiliary designs, but they still cannot rescue tooth inclination during tooth retraction period. For tooth translation, it may be a better clinical procedure to change the one-step aligner design to two-step process: tilting retraction and root control.

A Review of Alignment Optimization Research for Roads, Railways and Rail Transit Lines

Roads, railways and rail transit lines play major roles in transporting passengers and freight. In the design process for such transportation infrastructures, the alignment determination greatly affects their life-cycle performances. However, due to the great complexity associated with alignment design, conventional manual work is very time-consuming and laborious, which consequently prompts the flourishing development of intelligent alignment optimization (AO). Hitherto, with considerable invested efforts, numerous remarkable AO studies have been reported. In this work, we present the first-known literature review paper in this field from the past 25 years. First, a bibliometric visualization is conducted to show the overall characteristics of AO research. Then, existing mathematical models that formulate AO problems are reviewed. Particularly, GIS-based applications for AO are also analyzed in that part. Afterward, the intelligent solution methodologies for solving AO models are discussed. Moreover, two specific research topics, i.e., concurrent optimization of railroad alignments and station locations as well as the existing alignment recreation and redesign, are provided. Finally, we propose 12 possible research extensions and directions in this realm.

Automatic Design of the Horizontal Alignment of a Road Interchange: The Case of a Trumpet-Type

This paper investigated the automatic design of road interchanges in the framework of mathematical optimization. To introduce the approach, we focused on a trumpet-type interchange, and specifically on S-type and loop ramps. By analyzing all geometric elements, we propose a geometrical model that provides, from an appropriate decision vector, a complete parametrization of the ramps. We established safety and spatial constraints (including restrictions on passage through forbidden areas) and formulated a nonlinear optimization problem, the numerical solution of which gives the design of the interchange ramps. The goodness of the model and the accuracy of the method proposed for its numerical resolution was checked using an academic problem designed so that its solution can be analyzed easily. Finally, the practical usefulness of this methodology was shown in a real case study, redesigning an existing interchange on a Spanish highway.

A Recommendation Model for Highway Horizontal Curve Indicators Based on Machine Learning

The horizontal alignment design is the result of the designer’s comprehensive consideration of smooth alignment and satisfying multiple design goals such as safety, environmental protection and economy.Through analyzing a large number of highway horizontal design cases,the statistical laws of intersection spacing, declination angle and the relationship between them are introduced. Based on this and the machine learning algorithms, a horizontal basic curve indicator recommendation model suitable for the single intersection design and the double intersection design process is built. Finally, the reliability of the model is verified and evaluated by using the calculation accuracy, test set error and average difference.