The Design of a Three-Dimensional Physical Modeling System for Real-Time Groundwater Flows

In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-dimensional groundwater flows,making it impossible to validate groundwater flows simulated by numerical methods with physical modeling.

A combination of digital design and three-dimensional printing to assist treatment of thoracolumbar compression fractures using percutaneous kyphoplasty

Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved.

SAR regional all-azimuth observation orbit design for target 3D reconstruction

Three-dimensional(3D) synthetic aperture radar(SAR)extends the conventional 2D images into 3D features by several acquisitions in different aspects. Compared with 3D techniques via multiple observations in elevation, e.g. SAR interferometry(InSAR) and SAR tomography(TomoSAR), holographic SAR can retrieve 3D structure by observations in azimuth. This paper focuses on designing a novel type of orbit to achieve SAR regional all-azimuth observation(AAO) for embedded targets detection and holographic 3D reconstruction. The ground tracks of the AAO orbit separate the earth surface into grids. Target in these grids can be accessed with an azimuth angle span of360°, which is similar to the flight path of airborne circular SAR(CSAR). Inspired from the successive coverage orbits of optical sensors, several optimizations are made in the proposed method to ensure favorable grazing angles, the performance of 3D reconstruction, and long-term supervision for SAR sensors. Simulation experiments show the regional AAO can be completed within five hours. In addition, a second AAO of the same area can be duplicated in two days. Finally, an airborne SAR data process result is presented to illustrate the significance of AAO in 3D reconstruction.

Structural Design and Optimization of Comb-type Electric Bicycle Three-dimensional Parking Garage

With the reduction of urban land, the three-dimensional garage is increasingly built with its advantages of saving land. But the current three-dimensional garage is built for the car. It is hardly stereo parking garage for electric bicycles. This paper designed a hollow tower electric bicycle stereo parking garage with fork comb structure, based on the analysis of the characteristics of electric bicycles and the characteristics of existing three-dimensional garages. A fixed comb is mounted on the garage frame. The movable comb is mounted on the middle lift mechanism of the garage. The access of the vehicle is achieved by the exchange of the comb. The key comb structure was modeled using SolidWorks software and the stress distribution of the structure was analyzed. It was optimized by MATLAB software. The result shows that this structure can improve access efficiency. The quality of the comb structure can be minimized under the constraints of strength requirements.

Design of an Acoustic Levitator for Three-Dimensional Manipulation of Numerous Particles

We present a design of an acoustic levitator consisting of three pairs of opposite transducer arrays.Three orthogonal standing waves create a large number of acoustic traps at which the particles are levitated in mid-air.By changing the phase difference of transducer arrays,three-dimensional manipulation of particles is successfully realized.Moreover,the relationship between the translation of particles and the phase difference is experimentally investigated,and the result is in agreement with the theoretical calculation.This design can expand the application of acoustic levitation in many fields,such as biomedicine,ultrasonic motor and new materials processing.

Three-dimensional global interconnect based on a design window

Based on a stochastic wire length distributed model, the interconnect distribution of a three-dimensional integrated circuit （3D IC） is predicted exactly. Using the results of this model, a global interconnect design window for a giga-scale system-on-chip （SOC） is established by evaluating the constraints of 1） wiring resource, 2） wiring bandwidth, and 3） wiring noise. In comparison to a two-dimensional integrated circuit （2D IC） in a 130-nm and 45-nm technology node, the design window expands for a 3D IC to improve the design reliability and system performance, further supporting 3D IC application in future integrated circuit design.

Three-Dimensional Nonlinear Dynamic Model and Macro Control of Real Estate

In this paper, according to economics of real estate and macro-control theory, combine with the characteristics of the real estate market, macro-control of the real estate market is studied. After giving the dynamic model of three-dimensional nonlinear differential equations based on the total number of houses on the real estate business, the government’s averages housing investment funds and the standard price, systematically established the stability conditions of equilibrium point for this model. What’s more, through the use of extreme value analysis model, government funds have been invested in real estate business building devotion principles and the construction base of the real estate businessmen has also been estimated successfully. This provides the corresponding theoretical basis for government macro control policy-making.

Application of Digital Technology in Road and Bridge Design

With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to today’s digital software design era.Early designers relied on hand-drawn paper design forms which was time-consuming and error-prone.Digital support for road and bridge design not only saves the design time but the design quality has also achieved a qualitative leap.This paper engages in the application of digital technology in road and bridge design,to provide technical reference for China’s road and bridge engineering design units,to promote the popularity of Civil3D and other advanced design software in the field of engineering design and development,ultimately contributing to the sustainable development of China’s road and bridge engineering.

Set up the Mechanical Curriculum System Based on Three-Dimensional Design

The changes of design methods and manufacturing techniques have brought new requirements for engineers in enterprises, and therefore brought a challenge to the traditional teaching system of mechanical major courses. A new teaching system based on three-dimensional design to cultivate modern engineers with solid specialty bases and high creativity in a wide range of fields is presented.

Integration system research and development for three-dimensional laser scanning information visualization in goaf

An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.

Three-dimensional(3D) Printing Technology Assisted by Minimally Invasive Surgery for Pubic Rami Fractures

The feasibility of three-dimensional (3D) printing technology cgmbined with minimally invasive surgery in the treatment of pubic rami fractures was explored.From August 2015 to October 2017,a series of 30 patients who underwent surgical stabilization of their anterior pelvic ring (all utilizing the 3D printing technology)by one surgeon at a single hospital were studied.The minimally invasive incisions were made through anterior inferior cilia spine and pubic nodule.Data collected included the operative duration,the blood loss,the damage of the important tissue,the biographic union and therecovery of the function after the operation.Measurements on inlet and outlet pelvic cardiograph were made immediately post-operation and at all follow-up clinic visits.The scores of reduction and function were measured during follow-up.Results showed that the wounds of 30 patients were healed in the first stage,and there was no injury of important structures such as blood vessels and nerves.According to the Matta criteria,excellent effectiveness was obtained in 22 cases and good in 8 cases.According to the functional evaluation criteria of Majeed,excellent effectiveness was obtained in 21 cases and good in 9 cases.It was suggested that the 3D printing technology assisted by minimally invasive surgery can better evaluate the pelvic fracture before operation,which was helpful in plate modeling, and can shorten surgery duration and reduce intraoperative blood loss and complications. The positioning accuracy was improved,and better surgical result was finally achieved.

Three-Dimensional Ocean Sensor Networks:A Survey

The past decade has seen a growing interest in ocean sensor networks because of their wide applications in marine research,oceanography,ocean monitoring,offshore exploration,and defense or homeland security.Ocean sensor networks are generally formed with various ocean sensors,autonomous underwater vehicles,surface stations,and research vessels.To make ocean sensor network applications viable,efficient communication among all devices and components is crucial.Due to the unique characteristics of underwater acoustic channels and the complex deployment environment in three dimensional(3D) ocean spaces,new efficient and reliable communication and networking protocols are needed in design of ocean sensor networks.In this paper,we aim to provide an overview of the most recent advances in network design principles for 3D ocean sensor networks,with focuses on deployment,localization,topology design,and position-based routing in 3D ocean spaces.

Clinical Value of Stereoscopic Three-dimensional Echocardiography in Assessment of Atrial Septal Defects: Feasibility and Efficiency

Stereoscopic three-dimensional echocardiography（S-3DE） is a novel displaying technol-ogy based on real-time 3-dimensional echocardiography （RT-3DE）. Our study was to evaluate the feasibility and efficiency of S-3DE in the diagnosis of atrial septal defect （ASD） and its use in the guidance for transcatheter ASD occlusion. Twelve patients with secundum ASD underwent RT-3DE examination and 9 of the 12 were subjected to transcatheter closure of ASD. Stereoscopic vision was generated with a high-performance volume renderer with red-green stereoscopic glasses. S-3DE was compared with standard RT-3D display for the assessment of the shape, size, and the surrounding tis-sues of ASD and for the guidance of ASD occlusion. The appearance rate of coronary sinus and the mean formation time of the IVC, SVC were compared. Our results showed that S-3DE could measure the diameter of ASD accurately and there was no significant difference in the measurements between S-3DE and standard 3D display （2.89±0.73 cm vs 2.85±0.72 cm, P〉0.05; r=0.96, P〈0.05）. The appearance of coronary sinus for S-3DE was higher as compared with the standard 3D display （93.3% vs 100%）. The mean time of the IVC, SVC for S-3DE monitor was slightly shorter than that of the standard 3D display （11.0±3.8 s vs 10.3±3.6 s, P〉0.05）. The mean completion time of interven-tional procedure was shortened with S-3DE display as compared with standard 3D display （17.3±3.1 min vs 23.0±3.9 min, P〈0.05）. Stereoscopic three-dimensional echocardiography could improve the visualization of three-dimensional echocardiography, facilitate the identification of the adjacent structures, decrease the time required for interventional manipulation. It may be a feasible, safe, and efficient tool for guiding transcatheter septal occlusion or the surgical interventions.

Series-parallel Hybrid Vehicle Control Strategy Design and Optimization Using Real-valued Genetic Algorithm

Despite the series-parallel hybrid electric vehicle inherits the performance advantages from both series and parallel hybrid electric vehicle, few researches about the series-parallel hybrid electric vehicle have been revealed because of its complex co nstruction and control strategy. In this paper, a series-parallel hybrid electric bus as well as its control strategy is revealed, and a control parameter optimization approach using the real-valued genetic algorithm is proposed. The optimization objective is to minimize the fuel consumption while sustain the battery state of charge, a tangent penalty function of state of charge（SOC） is embodied in the objective function to recast this multi-objective nonlinear optimization problem as a single linear optimization problem. For this strategy, the vehicle operating mode is switched based on the vehicle speed, and an ＂optimal line＂ typed strategy is designed for the parallel control. The optimization parameters include the speed threshold for mode switching, the highest state of charge allowed, the lowest state of charge allowed and the scale factor of the engine optimal torque to the engine maximum torque at a rotational speed. They are optimized through numerical experiments based on real-value genes, arithmetic crossover and mutation operators. The hybrid bus has been evaluated at the Chinese Transit Bus City Driving Cycle via road test, in which a control area network-based monitor system was used to trace the driving schedule. The test result shows that this approach is feasible for the control parameter optimization. This approach can be applied to not only the novel construction presented in this paper, but also other types of hybrid electric vehicles.

A Real-time Concurrent Product and Process Design System for Mechanical Parts

A real time concurrent product and process design system for mechanical parts is described in this paper. It consists of integrated product model, the expert system of product manufacturability evaluation and the controller of concurrent design. With the help of the controller of concurrent design, each feature of a part can be designed and evaluated based on manufacturing knowledge and resources, and can be modified according to the results of evaluation. The machining method of design feature can be selected based on manufacturing knowledge. So real time concurrent product and process design can be implemented based on integrated product model that is established based on generalized feature. Products and its design process can be optimized with the help of this system. The information and function integration of product design process can be realized. The time to market and the cost of products can be reduced.

Prediction of three-dimensional elastic behavior of filament-wound composites based on the bridging model

This work provides a method to predict the three-dimensional equivalent elastic properties of the filament-wound composites based on the multi-scale homogenization principle.In the meso-scale,a representative volume element(RVE)is defined and the bridging model is adopted to establish a theoretical predictive model for its three-dimensional equivalent elastic constants.The results obtained through this method for the previous experimental model are compared with the ones gained respectively by experiments and classical laminate theory to verify the reliability of this model.In addition,the effects of some winding parameters,such as winding angle,on the equivalent elastic behavior of the filament-wound composites are analyzed.The rules gained can provide a theoretical reference for the optimum design of filament-wound composites.

Real-time Design Constraints in Implementing Active Vibration Control Algorithms

Although computer architectures incorporate fast processing hardware resources, high performance real-time implementation of a complex control algorithm requires an efficient design and software coding of the algorithm so as to exploit special features of the hardware and avoid associated architecture shortcomings. This paper presents an investigation into the analysis and design mechanisms that will lead to reduction in the execution time in implementing real-time control algorithms. The proposed mechanisms are exemplified by means of one algorithm, which demonstrates their applicability to real-time applications. An active vibration control （AVC） algorithm for a flexible beam system simulated using the finite difference （FD） method is considered to demonstrate the effectiveness of the proposed methods. A comparative performance evaluation of the proposed design mechanisms is presented and discussed through a set of experiments.

Three-Dimensional Velocity Distribution Measurement Using Ultrasonic Velocity Profiler with Developed Transducer

This study describes an ultrasonic velocity profiler that uses a new ultrasonic array transducer with unique 5-element configuration, with all five elements acting as transmitters and four elements as receivers. The receivers are designed to reduce the amount of uncertainty. As the fluid moves through this setup, four Doppler frequencies are obtained. The multi-dimensional velocity information along the measurement line can be reconstructed. The transducer has a compact geometry suitable for a wide range of applications, including narrow flow areas. The transducer’s basic frequency and sound pressure are selected and evaluated to be compatible with the application. First, to confirm the measurement ability, the measurement of the developed system in two-dimensional flow is validated by comparing it to the theoretical data. The uncertainty of measurement was within 15%. Second, the three-dimensional measurement in turbulent and swirling flow is proved experimentally to check the applicability of the proposed technique.

Design of the contingent royalty rate as related to the type of investment

This study investigates the design of the royalty rate in a first-price auction across three types of investments:incremental and lumpy with or without an exogenously given intensity.A bidder’s investment cost comprises private information.This,together with the stochastic evolution of the price of the output generated from the auctioned project,precludes the seller from setting the exact dates of investment with the winner.However,the seller can set the royalty rate to equate the winner’s royalty payment with the winner’s information rent so that the winner acts as if to maximize the seller’s revenue.We derive two main conclusions.First,compared with the case in which investment is lumpy with an exogenously given intensity,the seller can set a lower royalty rate on incremental investment because she can collect additional royalty payments from the winner,who has the option to later expand capacity.Second,the impact of output price uncertainty on the optimal royalty rate for the three types of investments exhibits two different patterns.When investment is either incremental or lumpy with an exogenously given intensity,greater output price uncertainty reduces the royalty rate.When investment is lumpy with variable intensity,greater output uncertainty raises the royalty rate.Our results imply that auctioneers may charge differential royalty rates for different types of investments.

Real-time Parallel Processing System Design and Implementation for Underwater Acoustic Communication Based on Multiple Processors

ADSP-TS101 is a high performance DSP with good properties of parallel processing and high speed.According to the real-time processing requirements of underwater acoustic communication algorithms,a real-time parallel processing system with multi-channel synchronous sample,which is composed of multiple ADSP-TS101s,is designed and carried out.For the hardware design,field programmable gate array(FPGA)logical control is adopted for the design of multi-channel synchronous sample module and cluster/data flow associated pin connection mode is adopted for multiprocessing parallel processing configuration respectively.And the software is optimized by two kinds of communication ways:broadcast writing way through shared bus and point-to-point way through link ports.Through the whole system installation,connective debugging,and experiments in a lake,the results show that the real-time parallel processing system has good stability and real-time processing capability and meets the technical design requirements of real-time processing.