Alignment Design Research Articles

Concurrent Optimization of Rail Transit Alignments and Station Locations

Designing urban rail transit systems is a complex problem, which involves the determination of station locations, track geometry, and various other system characteristics. Most of the previous rail transit route optimization studies have focused on the alignment design between predetermined stations, whereas a practical design process has to account for the complex interactions among railway alignments and station locations. This paper proposes a methodology for concurrently optimizing station locations and the rail transit alignment connecting those stations, by accommodating multiple system objectives, satisfying various design constraints, and integrating the analysis models with a geographical information system database. The methodology incorporates demand and station costs in the evaluation framework and employs a genetic algorithm for optimizing the decision variables for station locations, station types, and track alignments. It is expected that transit planners may greatly benefit from the proposed methodology, with which they can conveniently and efficiently optimize candidate alternatives. The Baltimore Red Line is used as a case study to demonstrate how the model can find very good solutions in regions with complex geography.

Leveraging FPGAs for Accelerating Short Read Alignment.

One of the key challenges facing genomics today is how to efficiently analyze the massive amounts of data produced by next-generation sequencing platforms. With general-purpose computing systems struggling to address this challenge, specialized processors such as the Field-Programmable Gate Array (FPGA) are receiving growing interest. The means by which to leverage this technology for accelerating genomic data analysis is however largely unexplored. In this paper, we present a runtime reconfigurable architecture for accelerating short read alignment using FPGAs. This architecture exploits the reconfigurability of FPGAs to allow the development of fast yet flexible alignment designs. We apply this architecture to develop an alignment design which supports exact and approximate alignment with up to two mismatches. Our design is based on the FM-index, with optimizations to improve the alignment performance. In particular, the n-step FM-index, index oversampling, a seed-and-compare stage, and bi-directional backtracking are included. Our design is implemented and evaluated on a 1U Maxeler MPC-X2000 dataflow node with eight Altera Stratix-V FPGAs. Measurements show that our design is 28 times faster than Bowtie2 running with 16 threads on dual Intel Xeon E5-2640 CPUs, and nine times faster than Soap3-dp running on an NVIDIA Tesla C2070 GPU.

A bi-objective optimization framework for three-dimensional road alignment design

Optimization of three-dimensional road alignments is a nonlinear non-convex optimization problem. The development of models that fully optimize a three-dimensional road alignment problem is challenging due to numerous factors involved and complexities in the geometric specification of the alignment. In this study, we developed a novel bi-objective optimization approach to solve a three dimensional road alignment problem where the horizontal and vertical alignments are optimized simultaneously. Two conflicting cost objective functions, earthwork cost and the utility cost, are cast in a bi-objective optimization problem. We numerically compare several multi-objective optimization solvers, and find that it is possible to determine the Pareto front in a reasonable time.

Application of Image Servo Alignment Module Design to Automatic Laminating Machine for Touch Panel

For general add-on touch panels, a touch-sensitive layer is attached to the outside of LCD panel. As the touch panel has a sensitive layer, it must be aligned with the display panel very well, the laminating precision is also required. The integration of this kind of equipment is complex, and the research and development of the equipments covers many topics of system integration. It is difficult to customize the products for different sizes or functions. This research used key technologies, including different space alignment design and unmarked alignment method, to create an easily operated image servo alignment system. Stable and rapid alignment results were obtained by parametric optimization. Finally, this module was applied to the industrial automatic laminating machine in practice for alignment and lamination.

The Feasibility of a Land Ferry System to Reduce Highway Maintenance Cost and Associated Externalities.

This study provides an economic evaluation for a Land Ferry, which is a rail system capable of carrying trucks and all other types of vehicles, passengers, and cargo. The Land Ferry system involves a sliding loading system to roll heavy loads onto a flatbed; as a result, loading and unloading of all vehicles and cargo could be accomplished simultaneously. The evaluation for this system included (1) the design of a new track alignment over which the Land Ferry system would run, (2) evaluation of various sources of power, (3) estimation of how many local jobs the Land Ferry would generate, and (4) a benefit-cost analysis. It was estimated that the Land Ferry would create over 45,788 temporary jobs in Nevada during the three-year construction period and 318 permanent jobs during operation. The majority of the benefits were attributed to savings in travel time ($356.4 M), vehicle operating costs ($1000.4 M), reduction of accidents ($544.6 M), and pavement maintenance ($503.2 M). These benefits would be a consequence of the shift of trucks from the highway, thus resulting in higher speeds, decrease fuel consumption, and decrease vehicle maintenance costs. The overall benefit-cost ratio of 1.7 implies a cost-effective project.

Computation-based Dynamic Driving Simulation for Evaluation of Mountain Roads with Complex Shapes: A Case Study

Lower standard rural roads with a design speed less than 40km/h account for more than 80% of total roadway network in China. In most situations, vehicles on these rural roads are of free traffic flow, and the driving stability of a vehicle is therefore mostly influenced by alignments and road surface. Single-vehicle run-off-road crashes are often associated with poor road conditions. Therefore, the improvement of alignment design of the roads can be effective to reduce the number of traffic accidents. This research targets at the analysis of driving in several sections of a four-class rural road in Yunan province, China, with varying alignments and complex shapes. In this context, a road creation module, a vehicle dynamics model, and driver module are established in computing environment, and integrated into a “roadway-driver-vehicle” virtual driving system. Driving simulations of a passenger car model on the test segments are conducted. Speed, driver workload, and ride comfort are analyzed in relation to varying geometric alignments. The simulation results show that: by balancing the design parameters of adjacent curve radii and the tangent length in-between, critical safety driving speed on lower standard rural roads can be obtained; the use of hairpin curves and the absence of spirals would lead to a rapid increase in both angular speed of steering wheel and lateral acceleration change rate, resulting in increasing driver nervousness and passenger discomfort.

탄소저감형 다차원 도로선형설계를 위한 솔루션 알고리즘 개발

Government efforts for green growth policy initiatives demand low-carbon technologies in the road construction industry. The purpose of this paper is to develop an algorithm of a road alignment design solution for establishing the multi-dimensional information, and to calculate carbon emission quantity due to the geometric design elements in the planning phase of road alignment. The paper developed a calculation method for carbon emission quantity by drawing a speed profile reflected in the operating speed, acceleration and deceleration, which are majors factor of carbon emissions while driving and by applying a carbon emission factor. From this effort, it enabled alignment planning to reduce carbon emission. Object-based parametric design methods of the cross-sections were proposed for alignment planning, and the paper demonstrated a BIM-based road alignment planning solution. The proposed solutions can provide multi-dimensional information on carbon emission quantity and cross section elements through driving simulation. It is expected to allow construction of eco-friendly roads by deriving optimal road alignment to minimize environmental costs.

Joint Iterative Interference Alignment and Energy Harvesting for Multi-User Networks

In a wireless network with multiple users, interferences cause performance degradation as well as provide extra opportunities for harvesting RF energies. In this work, a new joint design of interference alignment (IA) and energy harvesting (EH) that aims to reduce interferences to the desired user and harvest energies from the interferences when IA is inefficient is studied. Two iterative IA schemes, distributed IA (DIA) and IA via alternating minimization (IAAM) are considered. Based on a tradeoff decision criterion, the operation switches between IA and EH. Numerical results show that there is a tradeoff between information rate and harvested energy for both DIA and IAAM. The scheme with higher information rate often has smaller harvested energy.

No difference in patellar kinematics between fixed-bearing cruciate-retaining and cruciate-substituting total knee arthroplasty: a cadaveric investigation.

The influence of cruciate-ligament-retaining (CR-TKA) and cruciate-ligament-substituting (CS-TKA) TKA on tibiofemoral kinematics was analysed in many investigations. However, the influence on patellar kinematics is unclear so far. The aim of this study was to compare patellar kinematics of the natural knee with those after CR- and CS-TKA. Patellar kinematics of nine healthy whole-body cadaveric knees before and after CR- and CS-TKA was investigated using a commercial optical computer navigation system. Patellar kinematics of the healthy knee was compared with those after CR- and CS-TKA. No significant difference between the natural knee and the knee after TKA or between both types of TKA for patellar kinematics could be found. Interestingly, both types of TKA resulted in a more medial patellar shift and a contrary patellar tilt and rotation behaviour. CR- and CS-TKA resulted in smaller values for patellar epicondylar distance at all flexion angles. Our study found no influence of prosthesis type on patellar kinematics. Factors like component alignment and prosthesis design seem to be more important in terms of adequate restoration of patellar kinematics in TKA than whether choosing CR- or CS-TKA.

Linear Beamformer Design for Interference Alignment via Rank Minimization

This paper proposes a new framework for the design of transmit and receive beamformers for interference alignment (IA) without symbol extensions in multi-antenna cellular networks. We consider IA in a $G$ cell network with $K$ users/cell, $N$ antennas at each base station (BS) and $M$ antennas at each user. The proposed framework is developed by recasting the conditions for IA as two sets of rank constraints, one on the rank of interference matrices, and the other on the transmit beamformers in the uplink. The interference matrix consists of all the interfering vectors received at a BS from the out-of-cell users in the uplink. Using these conditions and the crucial observation that the rank of interference matrices under alignment can be determined beforehand, this paper develops two sets of algorithms for IA. The first part of this paper develops rank minimization algorithms for IA by iteratively minimizing a weighted matrix norm of the interference matrix. Different choices of matrix norms lead to reweighted nuclear norm minimization (RNNM) or reweighted Frobenius norm minimization (RFNM) algorithms with significantly different per-iteration complexities. Alternately, the second part of this paper devises an alternating minimization (AM) algorithm where the rank-deficient interference matrices are expressed as a product of two lower-dimensional matrices that are then alternately optimized. Simulation results indicate that RNNM, which has a per-iteration complexity of a semidefinite program, is effective in designing aligned beamformers for proper-feasible systems with or without redundant antennas, while RFNM and AM, which have a per-iteration complexity of a quadratic program, are better suited for systems with redundant antennas.

Octonary Resistance States in La0.7Sr0.3MnO3/BaTiO3/La0.7Sr0.3MnO3 Multiferroic Tunnel Junctions

General drawbacks of current electronic/spintronic devices are high power consumption and low density storage. A multiferroic tunnel junction (MFTJ), employing a ferroelectric barrier layer sandwiched between two ferromagnetic layers, presents four resistance states in a single device and therefore provides an alternative way to achieve high density memories. Here, an MFTJ device with eight nonvolatile resistance states by further integrating the design of noncollinear magnetization alignments between the ferromagnetic layers is demonstrated. Through the angle‐resolved tunneling magnetoresistance investigations on La0.7Sr0.3MnO3/BaTiO3/La0.7Sr0.3MnO3 junctions, it is found that, besides collinear parallel/antiparallel magnetic configurations, the MFTJ shows at least two other stable noncollinear (45° and 90°) magnetic configurations. Combining the tunneling electroresistance effect caused by the ferroelectricity reversal of the BaTiO3 barrier, an octonary memory device is obtained, representing potential applications in high density nonvolatile storage in the future.

Design of Transfer Alignment for Micro-Inertial Attitude Measurement System Based on Distributed

In view of the specific environment of the reconnaissance UAV (Unmanned Aerial Vehicle), it is necessary to design a micro-inertial attitude measurement system. The ground-demo of the distributed micro-inertial attitude measurement system was set up. Then the attitude error measurement equation was deduced. Based on this, the Kalman filter using the “velocity and attitude” matching algorithm was designed. Through vehicle test, the experimental results show that the precisions of horizontal angle and azimuth angle are superior to 1.5′ and 2.3′ respectively by the proposed algorithm. All these characteristics show that the scheme is feasible and can provide reference for the engineering application of the distributed micro-inertial attitude measurement system.

Limited Feedback Design for Interference Alignment on Two-Cell Interfering MIMO-MAC

This paper considers limited feedback for a two-cell interfering multiple-input–multiple-output multiple-access channel (MIMO-MAC). We propose a QR decomposition-based interference alignment (QRD-IA) scheme for efficient limited feedback and investigate the conditions for the antenna configuration. We characterize the interference leakage caused by quantization error as a function of the number of feedback bits. To minimize the interference leakage, we further propose a quantized-precoder-based IA (QP-IA) scheme by modifying the proposed QRD-IA scheme. By characterizing the interference leakage of the QP-IA scheme, we investigate the number of feedback bits to maintain the degrees of freedom (DOFs) in the two-cell interfering MIMO-MAC and a feedback bit allocation algorithm to improve the sum rate. From simulation results, we demonstrate that our proposed schemes can provide better sum-rate performance than the existing scheme using the same number of feedback bits, and our feedback bit allocation algorithm provides a higher sum rate compared with equal feedback bit allocation.

Research on the horizontal curve's radius under coupling effects of uneven adhesion coefficient and crosswind

In order to study the effects of uneven adhesion coefficient and crosswind on alignment design indexes, a six-axle semi-trailer is selected as the typical vehicle model to investigate the effects of uneven adhesion coefficient caused by superelevation under the condition of rainfall on the truck's lateral stability, quantifying the crosswind using TruckSim. Based on the basic theory of vehicle dynamics, vehicle safety driving model is established. Also, the minimum radius is calculated with the consideration of uneven adhesion coefficient and crosswind. The results show that the effects of uneven adhesion coefficient and crosswind on the truck's lateral stability increase with the increasing of the truck's speed. Truck's lateral slide instability begins to appear when crosswind grade grows up to 9 or above. According to sensitive analysis, speed, rainfall, crosswind, and the interaction of the speed and rainfall have significant influences on the truck's lateral stability. The results quantify the effects of uneven adhesion coefficient and crosswind on truck's lateral stability. The advised index for horizontal curve design control is proposed, which provides a good reference for road safety design and safety protective measures. It can also provide theoretical basis and guidelines for highway safe operation in the windy and rainy areas.

Multi-Resolution Codebook and Adaptive Beamforming Sequence Design for Millimeter Wave Beam Alignment

Millimeter wave (mm-wave) communication is expected to be widely deployed in fifth generation (5G) wireless networks due to the substantial bandwidth available for licensed and unlicensed use at mm-wave frequencies. To overcome the higher path loss observed at mm-wave bands, most prior work focused on the design of directional beamforming using analog and/or hybrid beamforming techniques in large-scale multiple-input multiple-output systems. Obtaining potential gains from highly directional beamforming in practical systems hinges on sufficient levels of channel estimation accuracy, where the problem of channel estimation becomes more challenging due to the substantial training overhead needed to sound all directions using a high-resolution narrow beam. In this paper, we consider the design of multi-resolution beamforming sequences to enable the system to quickly search out the dominant channel direction for single-path channels. The resulting design generates a multilevel beamforming sequence that strikes a balance between minimizing the training overhead and maximizing beamforming gain, where a subset of multilevel beamforming vectors is chosen adaptively to maximize the average data rate within a constrained time. We propose an efficient method to design a hierarchical multi-resolution codebook utilizing a Butler matrix, i.e., a generalized discrete Fourier transform matrix. Numerical results show the effectiveness of the proposed algorithm.

Optimal Transceiver Design for Interference Alignment Based Cognitive Radio Networks

Interference alignment (IA) can effectively eliminate the interference among users in cognitive radio (CR) networks. Nevertheless, to further increase the transmission rate of the primary user (PU) and guarantee its priority, we propose an optimal transceiver design (OTD) scheme for IA-based CR networks in this letter. In the OTD scheme, two partial-IA based algorithms are proposed to design the precoding matrices of SUs, in which the interference is aligned at the primary receiver with much lower overhead and complexity. Then the PU's precoding matrix is designed to maximize its throughput accordingly. To further improve the performance of SUs, their decoding matrices are re-designed. Simulation results are presented to show the effectiveness of the proposed scheme.

Desktop aligner for fabrication of multilayer microfluidic devices.

Multilayer assembly is a commonly used technique to construct multilayer polydimethylsiloxane (PDMS)-based microfluidic devices with complex 3D architecture and connectivity for large-scale microfluidic integration. Accurate alignment of structure features on different PDMS layers before their permanent bonding is critical in determining the yield and quality of assembled multilayer microfluidic devices. Herein, we report a custom-built desktop aligner capable of both local and global alignments of PDMS layers covering a broad size range. Two digital microscopes were incorporated into the aligner design to allow accurate global alignment of PDMS structures up to 4 in. in diameter. Both local and global alignment accuracies of the desktop aligner were determined to be about 20 μm cm(-1). To demonstrate its utility for fabrication of integrated multilayer PDMS microfluidic devices, we applied the desktop aligner to achieve accurate alignment of different functional PDMS layers in multilayer microfluidics including an organs-on-chips device as well as a microfluidic device integrated with vertical passages connecting channels located in different PDMS layers. Owing to its convenient operation, high accuracy, low cost, light weight, and portability, the desktop aligner is useful for microfluidic researchers to achieve rapid and accurate alignment for generating multilayer PDMS microfluidic devices.

Robust stability analysis of H∞-SGQKF and its application to transfer alignment

In this paper, the authors analyze the stochastic stability of the H∞ Sparse-grid Quadrature Kalman Filtering (H∞-SGQKF) used in nonlinear stochastic discrete-time systems with nonlinear state dynamic equation and nonlinear transition function. Using some standard results from estimation accuracy level of multidimensional sparse-grid theories as well as stochastic stability theories, we have developed the robust stability of nonlinear SGQKF under stochastic uncertainties. It is shown that estimation errors remain bounded if the system satisfies sufficient conditions, and that it is possible to improve stochastic stability by increasing system noise covariance matrixes, adjusting the noise robustness parameter γ and demonstrating the lower bound of noise robustness parameter. Finally, the H∞-SGQKF is applied to the design of Near-space hypersonic vehicle transfer alignment. The numerical simulation of the designed filter validates the effectiveness of the proposed filtering stochastic stability.

Preliminary Roadway Alignment Design: A Spatial-Data Optimization Approach

Preliminary Roadway Alignment Design: A Spatial-Data Optimization Approach

Quality of Slab Track Construction – Track Alignment Design and Track Geometry

Abstract The slab track superstructure design (without ballast) is a perspective construction especially for building tunnels and bridges in the modernized sections of railway tracks in Slovakia. Monitoring of the structure described in this article is focused on the transition areas between standard structure with ballast and slab track construction.