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D2EA: Depict the Epidemic Picture of COVID-19 LIU Chenzhengyi (刘陈正轶), ZHAO Jingwei (赵经纬), LIU Guohang (刘国航), GAO Yuanning (高远宁), GAO Xiaofeng (高晓沨) J Shanghai Jiaotong Univ Sci    2020, 25 (2): 165-176.   DOI: 10.1007/s12204-020-2170-7 Abstract （467）      PDF （748KB）（730）       Knowledge map    The outbreak of coronavirus disease 2019 (COVID-19) has aroused a global alert. To release social panic and guide future schedules, this article proposes a novel mathematical model, the Delay Differential Epidemic Analyzer (D2EA), to analyze the dynamics of epidemic and forecast its future trends. Based on the traditional Susceptible-Exposed-Infectious-Recovered (SEIR) model, the D2EA model innovatively introduces a set of quarantine states and applies both ordinary differential equations and delay differential equations to describe the transition between two states. Potential variations of practical factors are further considered to reveal the true epidemic picture. In the experiment part, we use the D2EA model to simulate the epidemic in Hubei Province. Fitting to the collected real data as non-linear optimization, the D2EA model forecasts that the accumulated confirmed infected cases in Hubei Province will reach the peak at the end of February and then steady down. We also evaluate the effectiveness of the quarantine measures and schedule the date to reopen Hubei Province. Reference | Related Articles | Metrics

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Review on Corrosion Characteristics of Porous Titanium Alloys Fabricated by Additive Manufacturing GAI Xin, (盖欣), BAI Yun (白芸), LI Shujun (李述军), WANG Liao (王燎), AI Songtao (艾松涛), HAO Yulin (郝玉琳), YANG Rui (杨锐), DAI Kerong (戴尅戎) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 416-430.   DOI: 10.1007/s12204-021-2314-4 Abstract （239）      PDF （1891KB）（418）       Knowledge map    Porous titanium and its alloys have been considered as promising implants owing to their low elastic  modulus and capability to provide channels for bone growth. Currently, additive manufacturing (3D printing)  techniques have been successfully applied to produce porous titanium alloys owing to the advantages of controllable  and precise fabrication. Considering the safety aspect, an understanding of corrosion in porous titanium alloys  and the corresponding mechanisms is important for their long-term application in the human body. In this  paper, the recent progress in improving the corrosion properties of porous titanium alloys fabricated via 3D  printing techniques is reviewed. The effects of pore type, porosity, electrolyte, and modification of the material  on the corrosion properties of porous titanium alloys are introduced and discussed. In addition, the limitations of  traditional methods for measuring the corrosion performance of porous titanium alloys were analysed. Perspectives  for evaluating and improving the corrosion performance of porous titanium alloys using new methods are provided.  Reference | Related Articles | Metrics

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Preliminary Assessment of the COVID-19 Outbreak Using 3-Staged Model e-ISHR LI Sijia (李斯佳), SONG Kun (宋琨), YANG Boran (杨博然), GAO Yucen (高宇岑), GAO Xiaofeng (高晓沨) J Shanghai Jiaotong Univ Sci    2020, 25 (2): 157-164.   DOI: 10.1007/s12204-020-2169-0 Abstract （452）      PDF （472KB）（521）       Knowledge map    The outbreak of coronavirus disease 2019 (COVID-19) in Wuhan has aroused widespread concern and attention from all over the world. Many articles have predicted the development of the epidemic. Most of them only use very basic SEIR model without considering the real situation. In this paper, we build a model called e-ISHR model based on SEIR model. Then we add hospital system and time delay system into the original model to simulate the spread of COVID-19 better. Besides, in order to take the government’s control and people’s awareness into consideration, we change our e-ISHR model into a 3-staged model which effectively shows the impact of these factors on the spread of the disease. By using this e-ISHR model, we fit and predict the number of confirmed cases in Wuhan and China except Hubei. We also change some of parameters in our model. The results indicate the importance of isolation and increasing the number of beds in hospital. Reference | Related Articles | Metrics

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Intelligent-Assist Algorithm for Remote Shared-Control Driving Based on Game Theory QIAO Bangjun∗ (乔邦峻), LI Huanghe (李黄河), WU Xiaodong (吴晓东) J Shanghai Jiaotong Univ Sci    2021, 26 (5): 615-625.   DOI: 10.1007/s12204-021-2351-z Abstract （154）      PDF （759KB）（299）       Knowledge map    Contemporary autonomous-driving technology relies on good environmental-perception systems and high-precision maps. For unknown environments or scenarios where perception fails, a human-in-the-loop remote-driving system can effectively complement common solutions, although safety remains an issue for its application. A haptic shared-control algorithm based on non-cooperative game theory is presented in this paper. The algorithm generates collision-free reference paths with model predictive control and predicts the driver’s path using a two-point preview model. Man-machine torque interaction is modeled as a Nash game, and the assist system’s degree of intervention is regulated in real time, according to assessments of collision risk and the driver’s concentration. Simulations of several representative scenarios demonstrate how the proposed method improves driving safety, while respecting driver decisions. Reference | Related Articles | Metrics

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Prediction of COVID-19 Outbreak in China and Optimal Return Date for University Students Based on Propagation Dynamics HUANG Ganyu (黄甘雨), PAN Qiaoyi (潘荍仪), ZHAO Shuangying (赵双楹), GAO Yucen (高宇岑), GAO Xiaofeng (高晓沨) J Shanghai Jiaotong Univ Sci    2020, 25 (2): 140-146.   DOI: 10.1007/s12204-020-2167-2 Abstract （591）      PDF （550KB）（553）       Knowledge map    On 12 December 2019, a novel coronavirus disease, named COVID-19, began to spread around the world from Wuhan, China. It is useful and urgent to consider the future trend of this outbreak. We establish the 4+1 penta-group model to predict the development of the COVID-19 outbreak. In this model, we use the collected data to calibrate the parameters, and let the recovery rate and mortality change according to the actual situation. Furthermore, we propose the BAT model, which is composed of three parts: simulation of the return rush (Back), analytic hierarchy process (AHP) method, and technique for order preference by similarity to an ideal solution (TOPSIS) method, to figure out the best return date for university students. We also discuss the impacts of some factors that may occur in the future, such as secondary infection, emergence of effective drugs, and population flow from Korea to China. Reference | Related Articles | Metrics

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Biomechanical Analysis of Personalised 3D-Printed Clavicle Plates of Different Materials to Treat Midshaft Clavicle Fractures CHENG Rongshan, (程荣山), JIANG Ziang, (蒋子昂), DIMITRIOU Dimitris, GONG Weihua, (龚伟华), TSAI Tsung-Yuan, (蔡宗远) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 259-266.   DOI: 10.1007/s12204-021-2291-7 Abstract （323）      PDF （1656KB）（280）       Knowledge map    This study was aimed at comparing the biomechanical performance of personalised 3D-printed clavicle  plates of different materials to treat midshaft clavicle fractures with the finite element (FE) method. The FE  model of a fractured clavicle with a personalised 3D-printed clavicle plate and screws was constructed. Three  types of materials were simulated, including stainless steel, titanium alloy, and magnesium alloy. Two loading  conditions (axial compression and inferior bending) were applied at the distal end of the clavicle to simulate arm  abduction. Plate stiffness, peak stress, and bone strain at the clavicle fracture site were measured and compared.  The stiffness of the stainless steel clavicle plate was significantly greater than that of the titanium alloy clavicle  plate. The stiffness of the magnesium alloy clavicle plate was similar to that of the intact clavicle; peak stress  of the magnesium alloy clavicle plate was the lowest; thus, it had less stress-shielding effects on bone formation.  The magnesium alloy clavicle plate was more likely to form bone by distributing proper strain at the clavicle  fracture site. According to the influence of different materials on the tensile strength, magnesium alloy clavicle  plates might be preferred owing to their bionic stiffness in the treatment of patients with a low risk of falling. For  patients who engage in contact sports, a titanium alloy clavicle plate might be more suitable. Reference | Related Articles | Metrics

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Numerical Study on Separation of Circulating Tumor Cell Using Dielectrophoresis in a Four-Electrode Microfluidic Device WANG Yukuna (王雨坤), DING Xiantingb (丁显廷), ZHANG Zhinana (张执南) J Shanghai Jiaotong Univ Sci    2023, 28 (4): 391-.   DOI: 10.1007/s12204-022-2459-9 Abstract （192）      PDF （1462KB）（176）       Knowledge map    This numerical study proposes a cell sorting technique based on dielectrophoresis (DEP) in a microfluidic chip. Under the joint effect of DEP and fluid drag, white blood cells and circulating tumor cells are separated because of different dielectric properties. First, the mathematical models of device geometry, single cell, DEP force, electric field, and flow field are established to simulate the cell motion. Based on the simulation model, important boundary parameters are discussed to optimize the cell sorting ability of the device. A proper matching relationship between voltage and flow rate is then provided. The inlet and outlet conditions are also investigated to control the particle motion in the flow field. The significance of this study is to verify the cell separating ability of the microfluidic chip, and to provide a logistic design for the separation of rare diseased cells. Reference | Related Articles | Metrics

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Electric vehicle charging situation awareness for charging station ultra-short-term load forecast SHI Yiwei1 (史一炜), LIU Zeyu1 (刘泽宇), FENG Donghan1∗ (冯冬涵), ZHOU Yun1∗ (周 云), ZHANG Kaiyu2 (张开宇), LI Hengjie3 (李恒杰) J Shanghai Jiaotong Univ Sci    2023, 28 (1): 28-38.   DOI: 10.1007/s12204-023-2566-2 Abstract （192）      PDF （1518KB）（172）       Knowledge map    Electric vehicles (EVs) are expected to be key nodes connecting transportation–electricity–communication networks. Advanced automotive electronics technologies enhance EVs’ perception, computing, and communication capacity, which in turn can boost the operational efficiency of intelligent transportation systems (ITSs). EVs couple the ITS to the power system, providing a promising solution to charging congestion and transformer overload via navigation and forecasting approaches. This study proposes a privacy-preserving EV charging situation awareness framework and method to forecast the ultra-short-term load of charging stations. The proposed method only relies on public information from commercial service providers. In the case study, data are powered by the Baidu LBS cloud and EV-SGCC platform, and the experiment is conducted within an area of Pudong New District in Shanghai. Based on the results, the charging load of charging stations can be adequately forecasted more than 1 min ahead with low communication and computing power requirements. This research provides the basis for further studies on operation optimization and electricity market transaction of charging stations. Reference | Related Articles | Metrics

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Two Generative Design Methods of Hospital Operating Department Layouts Based on Healthcare Systematic Layout Planning and Generative Adversarial Network ZHAO Chaowang (赵朝望), YANG Jian (杨健), XIONG Wuyue (熊吴越), LI Jiatong (李佳潼) J Shanghai Jiaotong Univ Sci    2021, 26 (1): 103-115.   DOI: 10.1007/s12204-021-2265-9 Abstract （455）      PDF （1551KB）（248）       Knowledge map    With the increasing demands of health care, the design of hospital buildings has become increasingly demanding and complicated. However, the traditional layout design method for hospital is labor intensive, time consuming and prone to errors. With the development of artificial intelligence (AI), the intelligent design method has become possible and is considered to be suitable for the layout design of hospital buildings. Two intelligent design processes based on healthcare systematic layout planning (HSLP) and generative adversarial network (GAN) are proposed in this paper, which aim to solve the generation problem of the plane functional layout of the operating departments (ODs) of general hospitals. The first design method that is more like a mathematical model with traditional optimization algorithm concerns the following two steps: developing the HSLP model based on the conventional systematic layout planning (SLP) theory, identifying the relationship and flows amongst various departments/units, and arriving at the preliminary plane layout design; establishing mathematical model to optimize the building layout by using the genetic algorithm (GA) to obtain the optimized scheme. The specific process of the second intelligent design based on more than 100 sets of collected OD drawings includes: labelling the corresponding functional layouts of each OD plan; building image-to-image translation with conditional adversarial network (pix2pix) for training OD plane layouts, which is one of the most representative GAN models. Finally, the functions and features of the results generated by the two methods are analyzed and compared from an architectural and algorithmic perspective. Comparison of the two design methods shows that the HSLP and GAN models can autonomously generate new OD plane functional layouts. The HSLP layouts have clear functional area adjacencies and optimization goals, but the layouts are relatively rigid and not specific enough. The GAN outputs are the most innovative layouts with strong applicability, but the dataset has strict constraints. The goal of this paper is to help release the heavy load of architects in the early design stage and present the effectiveness of these intelligent design methods in the field of medical architecture. Reference | Related Articles | Metrics

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Travel Intention of Electric Vehicle Sharing based on Theory of Multiple Motivations BAO Lewen (鲍乐雯), MIAO Rui, ∗ (苗 瑞), CHEN Zhihua (陈志华), ZHANG Bo (张 博), GUO Peng (郭 鹏), MA Yuze (马宇泽) J Shanghai Jiaotong Univ Sci    2023, 28 (1): 1-9.   DOI: 10.1007/s12204-023-2563-5 Abstract （388）      PDF （467KB）（127）       Knowledge map    Determining the travel intention of residents with shared electric vehicles (EVs) is significant for promoting the development of low-carbon transportation, considering that common problems such as high idle rate and lack of attractiveness still exist. To this end, a structural equation model (SEM) based on the theory of multiple motivations is proposed in this paper. First, the influencing motivations for EV sharing are divided into three categories: consumer-driven, program-driven, and enterprise-driven motivations. Then, the intentions of residents in Shanghai to travel with shared EVs are obtained through a survey questionnaire. Finally, an SEM is constructed to analyze quantitatively the impact of different motivations on the travel intention. The results show that consumer-driven motivations with impact weights from 0.14 to 0.63 have the overwhelming impact on travel intention, compared to program-driven motivations with impact weights from ?0.14 to 0.15 and enterprise-driven motivations with impact weights from 0.02 to 0.06. In terms of consumer-driven motivations, the weight of green travel awareness is the highest. The implications of these results on the policy to enable large-scale implementation of shared EVs are discussed from the perspectives of the resident, enterprise, and government. Reference | Related Articles | Metrics

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Integrated Hydraulic-Driven Wearable Robot for Knee Assistance ZHAO Yafei (赵亚飞), HUANG Chaoyi (黄超逸), ZOU Yuging(邹玉莹), ZOUKehan(邹可涵), zoU Xiaogang(邹笑阳), XUE .Jiaqi(薛嘉琦), LI Xiaoting(李晓婷), KOH Keng Huat, WANG Xiaojun(王小军), LAI Wai Chiu King(赖伟超), HU Yong(胡勇), XI Ning(席宁), WANG Zheng(王峥) J Shanghai Jiaotong Univ Sci    2023, 28 (3): 289-295.   DOI: 10.1007/s12204-023-2602-2 Abstract （306）      PDF （1156KB）（135）       Knowledge map    Age-related diseases can lead to knee joint misfunction, making knee assistance necessary through the use of robotic wearable braces. However, existing wearable robots face challenges in force transmission and human motion adaptation, particularly among the elderly. Although soft actuators have been used in wearable robots, achieving rapid response and motion control while maintaining portability remains challenging. To address these issues, we propose a soft-robotic knee brace system integrated with multiple sensors and a direct-drive hydraulic actuation system. This approach allows for controlled and rapid force output on the portable hydraulic system. The multi-sensor feedback structure enables the robotic system to collaborate with the human body through human physiological signal and body motion information. The human user tests demonstrate that the knee robot provides assistive torques to the knee joint by being triggered by the electromyography signal and under human motion control. Reference | Related Articles | Metrics

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Simulation of Bimodal Fiber Distribution Effect on Transient Accumulation of Particles During Filtration AKAMPUMUZA Obed, WU Jiajun (吴佳骏), QUAN Zhenzhen (权震震), QIN Xiaohong (覃小红) J Shanghai Jiaotong Univ Sci    2021, 26 (2): 176-185.   DOI: 10.1007/s12204-020-2251-7 Abstract （273）      PDF （1849KB）（156）       Knowledge map    Modeling has become phenomenal in developing new products. In the case of filters, one of the most applied procedures is via the construction of idealized physical computational models bearing close semblance to real filter media. It is upon these that multi-physics tools were applied to analyze the flow of fluid and the resulting typical performance parameters. In this work, two 3D filter membranes were constructed with MATLAB; one had a random distribution of unimodal nanofibers, and the other, a novel modification, formed a bimodal distribution; both of them had similar dimensions and solid volume fractions. A comparison of their performance in a dust-loading environment was made by using computational fluid dynamic-discrete element method (CFD-DEM) coupling technique in STAR-CCM+. It was found that the bimodal nanofiber membrane greatly improved the particle capture efficiency. Whereas this increased the pressure drop, the gain was not too significant. Thus, overall, the results of the figure of merit proved that adopting a bimodal formation improved the filter's quality. Reference | Related Articles | Metrics

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Physical Characterization of Ionic Liquid-Modified Polyvinyl Alcohol and Sodium Thiocyanate Polymer Electrolytes for Electrochemical Double-Layer Capacitor Application AZEMTSOP Manfo Theodore , MEHRA Ram Mohan , KUMAR Yogesh , GUPTA Meenal J Shanghai Jiaotong Univ Sci    2023, 28 (2): 161-171.   DOI: 10.1007/s12204-021-2397-y Abstract （295）      PDF （1140KB）（110）       Knowledge map    Novel gel polymer electrolytes (GPEs) composed of polyvinyl alcohol (PVA) and sodium thiocyanate were developed via a solution casting technique. An ionic liquid (IL), 1-ethyl-3-methyl-imidazolium tricyanomethanide ([EMIM][TCM]), was doped into a polymer–salt complex system (PVA + NaSCN) to further enhance the conductivity. IL-doped polymer electrolyte (ILDPE) films were characterized using X-ray diffraction (XRD), polarized optical microscopy (POM), Fourier-transform infrared (FTIR) spectroscopy, and conductivity measurements. XRD was performed to check the degree of crystallinity and amorphicity of the ILDPE films, and the amorphicity of GPEs increased with the increase of the IL content. POM was employed to evaluate the changes in the surface morphology due to the inclusion of salt and IL in the PVA. The compositional nature of the GPE films was examined via FTIR studies. The electrical and electrochemical properties were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The maximum conductivity for the GPE film was estimated to be 1.10 × 10-5 S/cm for 6% (mass fraction) of IL in the polymer–salt complex. The ionic transference number was approximately 0.97. An electrochemical double-layer capacitor (EDLC) was built from optimized GPE films and reduced graphene oxide-based electrodes. The specific capacitance calculated from the cyclic voltammograms of the EDLC cells was 3 F/g. Reference | Related Articles | Metrics

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Using a Patient-Specific 3D-Printed Surgical Guide for High Tibial Osteotomy: A Technical Note JIANG Xu, (江旭), XIE Kai (谢凯), LI Bo (李波), HU Xumin (胡旭民), WU Haishan (吴海山), GAO Liangbin (高梁斌), WANG Liao (王燎), YAN Mengning (严孟宁) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 339-345.   DOI: 10.1007/s12204-021-2302-8 Abstract （281）      PDF （1004KB）（190）       Knowledge map    Patient-specific instrumentation (PSI) enables a more accurate alignment of the lower limbs in a high  tibial osteotomy (HTO) than in traditional surgery; however, the current design of commercial PSIs is not perfect.  Therefore, we designed a new patient-specific surgical guide to improve the accuracy of the osteotomy and verified  its reliability through a clinical operation. Here, we describe a patient with isolated medial-compartment bilateral  knee osteoarthritis, accompanied by a varus deformity of the proximal tibia. The patient was treated with HTO  using a patient-specific 3D-printed surgical guide. We concluded that the patient-specific 3D-printed surgical  guide improved the accuracy of the osteotomy and the alignment of the lower limb.  Reference | Related Articles | Metrics

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Ant Colony Algorithm Path Planning Based on Grid Feature Point Extraction LI Erchao∗ (李二超), QI Kuankuan (齐款款) J Shanghai Jiaotong Univ Sci    2023, 28 (1): 86-99.   DOI: 10.1007/s12204-023-2572-4 Abstract （196）      PDF （1196KB）（102）       Knowledge map    Aimed at the problems of a traditional ant colony algorithm, such as the path search direction and field of view, an inability to find the shortest path, a propensity toward deadlock and an unsmooth path, an ant colony algorithm for use in a new environment is proposed. First, the feature points of an obstacle are extracted to preprocess the grid map environment, which can avoid entering a trap and solve the deadlock problem. Second, these feature points are used as pathfinding access nodes to reduce the node access, with more moving directions to be selected, and the locations of the feature points to be selected determine the range of the pathfinding field of view. Then, based on the feature points, an unequal distribution of pheromones and a two-way parallel path search are used to improve the construction efficiency of the solution, an improved heuristic function is used to enhance the guiding role of the path search, and the pheromone volatilization coefficient is dynamically adjusted to avoid a premature convergence of the algorithm. Third, a Bezier curve is used to smooth the shortest path obtained. Finally, using grid maps with a different complexity and different scales, a simulation comparing the results of the proposed algorithm with those of traditional and other improved ant colony algorithms verifies its feasibility and superiority. Reference | Related Articles | Metrics

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Novel Data Placement Algorithm for Distributed Storage System  Based on Fault-Tolerant Domain SHI Lianxing (石连星), WANG Zhiheng (王志恒), LI Xiaoyong (李小勇) J Shanghai Jiaotong Univ Sci    2021, 26 (4): 463-470.   DOI: 10.1007/s12204-020-2253-5 Abstract （253）      PDF （1240KB）（147）       Knowledge map    The 3-replica redundancy strategy is widely used to solve the problem of data reliability in large-scale distributed storage systems. However, its storage capacity utilization is only 33%. In this paper, a data placement algorithm based on fault-tolerant domain (FTD) is proposed. Owing to the fine-grained design of the FTD, the data reliability of systems using two replicas is comparable to that of current mainstream systems using three replicas, and the capacity utilization is increased to 50%. Moreover, the proposed FTD provides a new concept for the design of distributed storage systems. Distributed storage systems can take FTDs as the units for data placement, data migration, data repair and so on. In addition, fault detection can be performed independently and concurrently within the FTDs. Reference | Related Articles | Metrics

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Sealing Performance of Pressure-Adaptive Seal LI Yuanfeng (李元丰), WANG Yiling (王怡灵), ZHANG Wanxin∗ (张万欣), LIU Jinian (刘冀念), MA Jialu (马加炉) J Shanghai Jiaotong Univ Sci    2022, 27 (6): 747-756.   DOI: 10.1007/s12204-022-2510-x Abstract （440）      PDF （2268KB）（167）       Knowledge map    A pressure-adaptive seal is developed to meet the demands of quick assembling and disassembling for an individual protection equipment in aerospace. The analysis model, which reflects the main characteristics of the seal structure, is built based on the finite element method and the Roth’s theory of rubber seal, and verified by the prototype test. The influences of precompression ratio, hardness of the sealing ring rubber, and friction coefficient on the sealing performance are investigated by variable parameter method. Results show that the model can describe the essential characteristics of the pressure-adaptive seal structure, which has good follow-up to the cavity pressure to achieve the purpose of pressure self-adaptive. The leakage rate correlates negatively with the precompression ratio of the sealing ring and the hardness of the sealing ring material, while is positively related to the friction coefficient between the sealing ring and the sealing edge. The maximum contact stress on sealing surface has negative correlation with the precompression ratio of the sealing ring, and positive correlation with the hardness of the seal ring material. The damage risk of the sealing ring increases with the increases of the precompression ratio of sealing ring, hardness of sealing ring material, and friction coefficient. Reference | Related Articles | Metrics

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Real-Time Deformation Simulation of Kidney Surgery Based on Virtual Reality JING Mengjie (荆梦杰), CUI Zhixin(崔志鑫), FU Hang (傅航), CHEN Xiaojun (陈晓军) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 290-297.   DOI: 10.1007/s12204-021-2295-3 Abstract （364）      PDF （3888KB）（128）       Knowledge map    Virtual reality-based surgery simulation is becoming popular with the development of minimally invasive  abdominal surgery, where deformable soft tissue is modelled and simulated. The mass-spring model (MSM)  and finite element method (FEM) are common methods used in the simulation of soft tissue deformation. However,  MSM has an issue concerning accuracy, while FEM has a problem with efficiency. To achieve higher accuracy and  efficiency at the same time, we applied a co-rotational FEM in the simulation of a kidney with a tumour inside,  achieving a real-time and accurate deformation simulation. In addition, we set a multi-model representation for  mechanical simulation and visual rendering. The implicit Euler method and conjugate gradient method were  adopted for setting and solving the linear system. For a realistic simulation of surgery, constraints outside the  kidney and between the kidney and tumour were set with two series of mechanical properties for the two models.  Experiments were conducted to validate the accuracy and real-time performance. Reference | Related Articles | Metrics

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Time-Varying Delay and Quantization Error LI Bin (李 斌), WAN Yi-ming (万一鸣), YE Hao (叶 昊) Journal of shanghai Jiaotong University (Science)    2011, 16 (5): 513-518.   DOI: 10.1007/s12204-011-1181-9 Abstract （1858）      PDF （303KB）（3055）       Knowledge map    Abstract:  Problems related to fault detection of networked control systems (NCSs) with both uncertain time-varying delay and quantization error are studied in this paper. A novel model with the form of polytopic uncertainty is given to represent the influences of both the time-varying delay and the quantization error, and then the reference model based method is used to design the residual generator that is robust to both unknown network-induced delay and unknown inputs. A numerical example is also given to illustrate the merits of the presented method. The proposed method can be regarded as an extension of the authors' former work, which can only deal with time-varying delay. Reference | Related Articles | Metrics

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High-Speed Fault-Tolerant Finite Impulse Response Digital Filter on Field Programmable Gate Array WU Tao (吴焘) J Shanghai Jiaotong Univ Sci    2021, 26 (4): 554-558.   DOI: 10.1007/s12204-020-2214-z Abstract （301）      PDF （720KB）（112）       Knowledge map    Some fast finite impulse response (FIR) filters use a large number of look-up tables (LUTs) to configure distributed random-access memories (RAMs) and save registers. The distributed RAMs store 2M precomputed sums of M permuted operands in order to simplify the accumulation, which lays similarity to the solution of Boolean satisfiability (SAT) problem. In this work, a high-speed fault-tolerant FIR digital filter on field programmable gate array (FPGA) is proposed for hardware implementation. A shift register and an RAM are used to arrange the data flow. Generally, an N-tap digital filter only requires N embedded multipliers on FPGA. The better performance is due to high-radix words and low-latency operations. A 32-tap 8-bit FIR digital filter enjoys a throughput of 9.17MB/s, taking 109 ns to calculate one convolution. In addition, a fault-tolerant scheme by majority logic is used to correct real-time errors within digital filters. Reference | Related Articles | Metrics

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Fabrication and Performance Investigation of Karma Alloy Thin Film Strain Gauge LEI Peng (雷鹏), ZHANG Congchun (张丛春), PANG Yawen (庞雅文), YANG Shenyong (杨伸勇), ZHANG Meiju (张梅菊) J Shanghai Jiaotong Univ Sci    2021, 26 (4): 454-462.   DOI: 10.1007/s12204-021-2315-3 Abstract （308）      PDF （1164KB）（125）       Knowledge map    Karma alloy thin film strain gauges were fabricated on alumina substrates by magnetron sputtering. The electrical properties of strain gauges annealed at different temperatures were then tested. The surface morphology and phase structure of the Karma alloy thin films were analyzed using X-ray diffraction and scanning electron microscopy. The effect of the annealing temperature on the performance of the Karma alloy thin film strain gauge was also investigated. As the annealing temperature increased, it was found that the resistivity of the thin films decreased, whereas the temperature coefficient of resistance (TCR) of the thin films increased. A Karma alloy thin film strain gauge was annealed at 200 °C, thereby obtaining a gauge factor of 1.7 and a corresponding TCR of 64.8 × 10-6 K-1. The prepared Karma alloy thin film strain gauge had a lower TCR than other strain gauges at room temperature. This result can provide a reference for the preparation and application of Karma alloy thin film strain gauges in specific scenarios. Reference | Related Articles | Metrics

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Effect of Attachment on Movement Control of the Central Incisor Using Invisible Orthodontics: In-Silico Finite Element Analysis PAN Shengxuan (潘晟轩), ZOU Diyang (邹第洋), PAN Xiaogang(潘晓岗), TSAI Tsung-Yuan (蔡宗远) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 383-390.   DOI: 10.1007/s12204-021-2309-1 Abstract （252）      PDF （1560KB）（102）       Knowledge map    We aimed to study the influence of attachment on central incisor movement control using invisible  orthodontics with different translation or rotation targets. In this study, cone-beam computerised tomography  was used to scan one 15-year-old volunteer’s teeth. Three-dimensional models of the mandibular central incisor,  removable orthodontic appliance, and a rectangular attachment were reconstructed. A non-linear finite element  simulation was used to analyse the influence of attachment on the stress distribution of the periodontal ligament of  the central incisor under tooth rotation, mesial translation, and labial-lingual translation. For mandibular central  incisor correction, using rectangular attachments increased the translation by up to 9.6%, increased the maximum  stress on the periodontal ligament during the mesial translation correction, and reduced unwanted labial-lingual tilt  by up to 40% during the rotation of the tooth. However, wearing an attachment during labial-lingual translation  had no significant effect on the orthodontic results of the mandibular central incisor. In the mandibular central  incisor’s invisible orthodontic, the rectangular attachment appliance increased the displacement and alleviated the  side effect after applying mesial translation and tooth rotation. For labial-lingual translation, the application of a  rectangular attachment had no pronounced effect on the results.  Reference | Related Articles | Metrics

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Bearing Incipient Fault Detection Method Based on Stochastic Resonance with Triple-Well Potential System LIU Ziwen (刘子文), XIAO Lei (肖雷), BAO Jinsong (鲍劲松), TAO Qingbao (陶清宝) J Shanghai Jiaotong Univ Sci    2021, 26 (4): 482-487.   DOI: 10.1007/s12204-020-2238-4 Abstract （341）      PDF （926KB）（116）       Knowledge map    Bearing incipient fault characteristics are always submerged in strong background noise with weak fault characteristics, so that the incipient fault is hard to detect. Stochastic resonance (SR) is accepted to be an effective way to detect the incipient; however, output saturation may occur if bistable SR is adopted. In this paper, a bearing incipient fault detection method is proposed based on triple-well potential system and SR mechanism. The achievement of SR highly replays on the nonlinear system which is adopted a triple-well potential function in this paper. Therefore, the parameters in the nonlinear system are optimized by particle swarm optimization algorithm, and the objective of optimization is to maximize the signal-to-noise ratio of the fault signal. After optimization, the optimal system parameters are obtained thereby the resonance effect is generated and the bearing incipient fault characteristic is enhanced. The proposed method is validated by simulation verification and engineering application. The results show that the method is effective to detect an incipient signal from heavy background noise and can obtain better outputs compared with bistable SR. Reference | Related Articles | Metrics

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Action-aware Encoder-Decoder Network for Pedestrian Trajectory Prediction FU Jiawei∗ (傅家威), ZHAO Xu (赵 旭) J Shanghai Jiaotong Univ Sci    2023, 28 (1): 20-27.   DOI: 10.1007/s12204-023-2565-3 Abstract （221）      PDF （775KB）（72）       Knowledge map    Accurate pedestrian trajectory predictions are critical in self-driving systems, as they are fundamental to the response- and decision-making of ego vehicles. In this study, we focus on the problem of predicting the future trajectory of pedestrians from a first-person perspective. Most existing trajectory prediction methods from the first-person view copy the bird’s-eye view, neglecting the differences between the two. To this end, we clarify the differences between the two views and highlight the importance of action-aware trajectory prediction in the first-person view. We propose a new action-aware network based on an encoder-decoder framework with an action prediction and a goal estimation branch at the end of the encoder. In the decoder part, bidirectional long short-term memory (Bi-LSTM) blocks are adopted to generate the ultimate prediction of pedestrians’ future trajectories. Our method was evaluated on a public dataset and achieved a competitive performance, compared with other approaches. An ablation study demonstrates the effectiveness of the action prediction branch. Reference | Related Articles | Metrics

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Clinical Observation of 3D Printing Technology in Insoles for Flexible Flatfoot Patients WANG Yitian (王一天), JIANG Wenbo (姜闻博), GAN Yaokai, (干耀恺), YU Yang (于洋), DAI Kerong, (戴尅戎) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 398-403.   DOI: 10.1007/s12204-021-2311-7 Abstract （303）      PDF （567KB）（118）       Knowledge map    Flatfoot is defined as the flattening of the medial arch of the foot, and it is classified into flexible  flatfoot and rigid flatfoot based on whether the flattening of the medial arch of the foot can be reset when  standing on toes. The insole is the most basic and common treatment, which is relatively cheaper and easier to  adopt. Three-dimensional (3D) printing, an emerging technology characterized by high machining accuracy and  use of various materials, can be utilised in personalised insoles, which have good application prospects. Further  research on the clinical effects of 3D-printed insoles is still needed. In this study, 64 cases of 3D-printed insoles  were clinically observed. The results showed that 3D-printed insoles had statistically positive effects in treating  flatfoot (P = 0.000 17), and with adjustment and adaptation, their comfort and clinical effect can be improved.  This study provides an empirical reference for further large-scale clinical control research.  Reference | Related Articles | Metrics

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Numerical Simulation Method of Scoliosis Orthosis Considering Muscle Factor LI Jian1,2(李健)，ZHU Ye1 (朱晔)，GUAN Tianmin1*(关天民) J Shanghai Jiaotong Univ Sci    2023, 28 (4): 486-.   DOI: 10.1007/s12204-022-2535-1 Abstract （55）      PDF （1381KB）（69）       Knowledge map    Adolescent idiopathic scoliosis seriously affects the physical and mental health of adolescents. In thepast, the research on therapeutic orthosis ignored the influence of muscle factors. Aimed at this problem, basedon the principle of reverse engineering, through the spine computed tomography data model of three-dimensionalreconstruction, muscle forces around the spine are imported into the spinal muscle force model and AnyBodysoftware is used for simulation. The geometric similarity and biomechanical effectiveness of the established modelare verified. In order to obtain the relationship among the applied orthopedic force, Cobb angle and vertebraldisplacement, a finite element model conforming to spinal anatomy is established, and then the biomechanicalanalysis of the finite element model of the scoliosis is carried out. Reasonable control of paravertebral muscles canplay a positive role in orthopedic treatment, and the fitting equation can provide a reference for doctors to applythe orthopedic force on patient. Reference | Related Articles | Metrics

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Numerical Study of Sodium Bentonite Extrusion into a Planar Fracture LIU Miaomiao (刘苗苗), LI Xiaoyue (李晓月), XU Yongfu (徐永福) J Shanghai Jiaotong Univ Sci    2021, 26 (2): 146-154.   DOI: 10.1007/s12204-021-2268-6 Abstract （299）      PDF （940KB）（129）       Knowledge map     As a candidate buffer/backfill material for high-level radioactive waste geological repositories, bentonite has numerous favorable properties, such as low permeability, high expansibility, and a high sorption capacity for radionuclides. The radionuclide-isolating performance of a buffer is strongly influenced by its extrusion. In this study, the bentonite extrusion process is explored: its basic mechanism can be considered free swelling of the bentonite. A 2D extrusion model of bentonite that is based on the 1D free swelling model of bentonite is presented. A numerical method is proposed to investigate the extrusion process of Na-bentonite into fractures over time under no-seepage conditions based on the free swelling model. The influences of the electrolyte concentration and dry density on the extrusion depth and mass of the bentonite are discussed, and the distribution of montmorillonite inside the bentonite is analysed. The rationale of the proposed bentonite extrusion model is then illustrated in comparison with the results of the bentonite extrusion test. Reference | Related Articles | Metrics

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A 12-bit 80 MS/s 2 mW SAR ADC with Deliberated Digital Calibration and Redundancy Schemes for Medical Imaging HAN Gang* (韩刚), WU Bin (吴斌), PU Yilin (蒲钇霖) J Shanghai Jiaotong Univ Sci    2022, 27 (2): 250-255.   DOI: 10.1007/s12204-021-2377-2 Abstract （216）      PDF （1130KB）（38）       Knowledge map    In this article, we presented a 12-bit 80MS/s low power successive approximation register (SAR)analog to digital converter (ADC) design. A simplified but effective digital calibration scheme was exploited to make the ADC achieve high resolution without sacrificing more silicon area and power efficiency. A modified redundancy technique was also adopted to guarantee the feasibility of the calibration and meantime ease the burden of the reference buffer circuit. The prototype SAR ADC can work up to a sampling rate of 80MS/s with the performance of > 10.5 bit equivalent number of bits (ENOB), < ±1 least significant bit (LSB) differential nonlinearity (DNL) & integrated nonlinearity (INL), while only consuming less than 2mA current from a 1.1V power supply. The calculated figure of merit (FoM) is 17.4 fJ/conversion-step. This makes it a practical and competitive choice for the applications where high dynamic range and low power are simultaneously required,such as portable medical imaging. Reference | Related Articles | Metrics

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Real-Time Trajectory Planning for On-road Autonomous Tractor-Trailer Vehicles SHEN Qiyue (沈琦越), WANG Bing (王 冰), WANG Chunxiang∗ (王春香) J Shanghai Jiaotong Univ Sci    2021, 26 (5): 722-730.   DOI: 10.1007/s12204-021-2362-9 Abstract （356）      PDF （1546KB）（146）       Knowledge map    Tractor-trailer vehicles, which are composed of a car-like tractor towing a passive trailer, have been widely deployed in the transportation industry, and trajectory planning is a critical step in enabling such a system to drive autonomously. Owing to the properties of being highly nonlinear and nonholonomic with complex dynamics, the tractor-trailer system poses great challenges to the development of motion-planning algorithms. In this study, an indirect trajectory planning framework for a tractor-trailer vehicle under on-road driving is presented to deal with the problem that the traditional planning framework cannot consider the feasibility and quality simultaneously in real-time trajectory generation of the tractor-trailer vehicle. The indirect planning framework can easily handle complicated tractor-trailer dynamics and generate high-quality, obstacle-free trajectory using quintic polynomial spline, speed pro?le optimization, forward simulation, and properly designed cost functions. Simulations under di?erent driving scenarios and trajectories with di?erent driving requirements are conducted to validate the performance of the proposed framework. Reference | Related Articles | Metrics

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Lightweight Method for Vehicle Re-identification Using Reranking Algorithm Based on Topology Information of Surveillance Network ZOU Yue (邹 悦), LI Lin (李 霖), YANG Xubo (杨旭波) J Shanghai Jiaotong Univ Sci    2021, 26 (5): 577-586.   DOI: 10.1007/s12204-021-2347-8 Abstract （247）      PDF （1353KB）（105）       Knowledge map    As an emerging visual task, vehicle re-identification refers to the identification of the same vehicle across multiple cameras. Herein, we propose a novel vehicle re-identification method that uses an improved ResNet-50 architecture and utilizes the topology information of a surveillance network to rerank the final results. In the training stage, we apply several data augmentation approaches to expand our training data and increase their diversity in a cost-effective manner. We reform the original RestNet-50 architecture by adding non-local blocks to implement the attention mechanism and replacing part of the batch normalization operations with instance batch normalization. After obtaining preliminary results from the proposed model, we use the reranking algorithm, whose core function is to improve the similarity scores of all images on the most likely path that the vehicle tends to appear to optimize the final results. Compared with most existing state-of-the-art methods, our method is lighter, requires less data annotation, and offers competitive performance. Reference | Related Articles | Metrics

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Meso-Scale Tearing Mechanism Analysis of Flexible Fabric Composite for Stratospheric Airship via Experiment and Numerical Simulation CHEN Yonglin (陈永霖), YANG Weidong (杨伟东), XIE Weicheng (谢炜程), WANG Xiaoliang (王晓亮), FU Gongyi∗ (付功义) J Shanghai Jiaotong Univ Sci    2022, 27 (6): 873-884.   DOI: 10.1007/s12204-022-2431-8 Abstract （110）      PDF （4194KB）（68）       Knowledge map    Stratospheric airships are controllable lighter-than-air aircraft and have great potential application in surveillance and communication. The envelopes, one of the main structures of a stratospheric airship, are generally made of flexible fabric composites to be lightweight, high strength, capable of containing lifting gas, and resistant to the harsh stratospheric environment. The composites, however, are prone to tearing. Hence, their tearing behavior has attracted great attention. This paper explores the meso-scale tearing mechanism of an envelope and the temperature influence on its tear strength via experiment and numerical simulation. Biaxial tear tests were conducted on cruciform specimens, which were contacted with liquids (cold alcohol or hot water) at different temperatures including -25, 20, 50, 80 °C. The specimens’ tear stresses were measured and the meso-scale tearing behavior was captured with a microscope. Besides, a novel finite element analysis model based on truss and spring elements was established to simulate the tearing behavior. It was found that the simulation result has a relative agreement with the tests. The simulation results show that the maximum tear stress of the envelope drops by 39.62% as the temperature rises from -60 °C to 80 °C and the tensile properties of yarns and matrix account for stress concentration around a crack tip. This work deeply reveals the meso-scale tearing mechanism of the envelope and provides a valuable reference for exploring tearing properties of flexible fabric composites. Reference | Related Articles | Metrics

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Control System of Two-Wheel Self-Balancing Vehicle REN Haoa∗ (任 淏), ZHOU Congb (周 聪) J Shanghai Jiaotong Univ Sci    2021, 26 (5): 713-721.   DOI: 10.1007/s12204-021-2361-x Abstract （287）      PDF （351KB）（85）       Knowledge map    This study mainly concerns a motion model and the main control algorithm of two-wheel self-balancing vehicle models. Details of the critical parameters fetching and output value of two-wheel self-balancing vehicle models are introduced, including those concerning balance control, speed control and direction control. An improved cascade coupling control scheme is proposed for two-wheel vehicles, based on a proportional-integral-derivative (PID) control algorithm. Moreover, a thorough comparison between a classic control system and the improved system is provided, and all aspects thereof are analyzed. It is determined that the control performance of the two-wheel self-balancing vehicle system based on the PID control algorithm is reliable, enabling the vehicle body to maintain balance while moving smoothly along a road at a fast average speed with better practical per-formance. Reference | Related Articles | Metrics

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Calibration Technology of Optical Fiber Strain Sensor CHEN Gang(陈刚), LIU Hongyue(刘宏月), GAO Ruiriang(高瑞翔) J Shanghai Jiaotong Univ Sci    2023, 28 (5): 551-559.   DOI: 10.1007/s12204-022-2406-9 Abstract （86）      PDF （1122KB）（62）       Knowledge map    As one of the hotspots of sensing technology at present, optical fiber sensor has the characteristics of small size, anti-electromagnetic interference, and easy networking, which plays an irreplaceable role in multiphysics parameter monitoring of complex electromagnetic environments. The precise calibration of the optical fiber strain sensor has great practical value in prolonging the survival rate of the sensor, improving the measurement accuracy, and meeting the needs of long-term monitoring. By reviewing the research status of strain sensor calibration method and fiber optic strain sensor calibration method, the advantages and disadvantages of the main methods are analyzed separately from the static and dynamic perspectives, and the development prospect of the calibration technology of optic fiber strain sensor is summarized. Reference | Related Articles | Metrics

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Accuracy Assessment of a Novel Radiographic Method to Evaluate Guided Bone Regeneration Outcomes Using a 3D-Printed Model SHI Junyu (史俊宇), LI Yuan (李元), ZHANG Xiao (张枭), ZHANG Xiaomeng (张晓梦), LAI Hongchang (赖红昌) J Shanghai Jiaotong Univ Sci    2021, 26 (3): 284-289.   DOI: 10.1007/s12204-021-2294-4 Abstract （336）      PDF （966KB）（89）       Knowledge map    The aim of this study was to evaluate the accuracy and reproducibility of a morphological contour  interpolation (MCI) based segmentation method for the volumetric measurement of bone grafts around implants.  Three 3D-printed models (one with a cylinder and two with a geometrically-complex form) were fabricated to  simulate implant placement with a simultaneous guided bone regeneration (GBR) procedure. All models were  scanned using a cone beam computed tomography (CBCT) instrument with the same parameters. The true  volumes of the bone grafts in the models were assessed using computer-aided calculation (controls). For the test  measurements, both manual and MCI-based methods were used. A comparison between the measured and true  volumes was performed to evaluate the accuracy. The coefficients of variation of repeated measurements were  calculated to evaluate the reproducibility. In addition, the execution time was recorded and a comparison between  the two methods was performed. The high accuracy of the MCI-based method was found with differences between  the measured value and actual volume, which never exceeded 7.3%. Excellent reproducibility was shown, with  coefficients of variation never exceeding 1.1%. A shorter execution time was observed for the MCI-based method  than for the manual method. Within the confines of this study, the MCI-based method may be suitable for  volumetric measurements of grafted bone around implants. Reference | Related Articles | Metrics

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Wavelet Transform-Based High-Definition Map Construction From a Panoramic Camera ZHUANG Hanyang (庄瀚洋), ZHOU Xuejun (周学军), WANG Chunxiang (王春香), QIAN Yuhan (钱宇晗) J Shanghai Jiaotong Univ Sci    2021, 26 (5): 569-576.   DOI: 10.1007/s12204-021-2346-9 Abstract （245）      PDF （1242KB）（124）       Knowledge map    High-definition (HD) maps are key components that provide rich topologic and semantic information for decision-making in vehicle autonomous driving systems. A complete ground orthophoto is usually used as the base image to construct the HD map. The ground orthophoto is obtained through inverse perspective transformation and image mosaicing. During the image mosaicing, multiple consecutive orthophotos are stitched together using pose information and image registration. In this study, wavelet transform is introduced to the image mosaicing process to alleviate the information loss caused by image overlapping. In the orthophoto wavelet transform, high-frequency and low-frequency components are fused using different strategies to form a complete base image with clearer local details. Experimental results show that the accuracy of the orthophotos generated using this method is improved. Reference | Related Articles | Metrics

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Novel Concentric Tube Robot Based on Double-Threaded Helical Gear Tube CHEN Weichi(陈韦池), LIU Haocheng(刘浩城), LI Zijian(李子建), GUO Jing, (郭靖), ZHAI Zhenkun(翟振坤), MENG Wei(孟伟) J Shanghai Jiaotong Univ Sci    2023, 28 (3): 296-306.   DOI: 10.1007/s12204-023-2595-x Abstract （186）      PDF （2087KB）（58）       Knowledge map    Nasopharyngeal carcinoma is a malignant tumor originating from the nasal mucosa. It is a malignant tumor of the head and neck. Concentric tube robot (CTR), as it can form a complicated shape and access hardto-reach lesions, is often used in minimally invasive surgeries. However, some CTRs are bulky because of their transmission design. In this paper, a light CTR based on double-threaded helical gear tube is proposed. Such a CTR is less cumbersome than the traditional CTR as its actuation unit is compact and miniaturized. The mapping relationship between the gear tube attitude and motor output angle is obtained by kinematic analysis. The precision, stability, and repeatability of the driving mechanism are tested. The experimental results show that the positioning error in the translation test is less than 0.3 mm, the rolling angle error in the stability test is less than 0.6?, and the error in the translation repeatability test is less than 0.005 mm. Finally, a tip-targeting test is performed using the new CTR, which verifies the feasibility of the CTR for surgeries. Reference | Related Articles | Metrics

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Curvature Adaptive Control Based Path Following for Automatic Driving Vehicles in Private Area SHI Qiang (师 强), ZHANG Jianlin (张建林), YANG Ming∗ (杨 明) J Shanghai Jiaotong Univ Sci    2021, 26 (5): 690-698.   DOI: 10.1007/s12204-021-2359-4 Abstract （389）      PDF （1349KB）（101）       Knowledge map    Path following refers to traveling along the desired path with automatic steering control, which is a crucial technology for automatic driving vehicles. Roads in private areas are highly irregular, resulting in a large curvature variation, which reduces the control accuracy of the path following. A curvature adaptive control (CAC) based path-following method was proposed to solve the problem mentioned above. Speci?cally, CAC takes advantage of the complementary characteristics in response to the path curvature ?uctuation of pure pursuit and front-wheel feedback and by combining the two methods further enhances the immunity of the control accuracy in response to a curvature ?uctuation. With CAC, the quantitative indices of the path curvature ?uctuation and control accuracy were constructed. The model between the path curvature ?uctuation and a dynamic parameter was identi?ed using the quantitative index of the control accuracy as the optimization target. The experimental results of a real vehicle indicate that the control accuracy of path following is further enhanced by its immunity in response to curvature ?uctuation improved by the CAC. In addition, CAC is easy to deploy and requires low demand for hardware resources. Reference | Related Articles | Metrics

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Strength-Toughness Improvement of 15-5PH Stainless Steel by Double Aging Treatment TE Rigele (特日格乐), ZHANG Yutuo, ∗ (张玉妥) J Shanghai Jiaotong Univ Sci    2023, 28 (2): 270-279.   DOI: 10.1007/s12204-021-2390-5 Abstract （286）      PDF （3166KB）（57）       Knowledge map    To obtain better strength-toughness balance of 15-5PH stainless steel, a double aging treatment is proposed to investigate the mechanical properties and microstructure evolution. In this study, Cu precipitates and reversed austenite played a determining role to improve strength-toughness combination. The microstructure was observed using electron backscattered diffraction, transmission electron microscopy and scanning transmission electron microscopy. The volume fractions of Cu precipitates and reversed austenite were calculated with Thermo-Calc software and measured by X-ray diffraction. The results showed that the reversed austenite is formed at the martensitic lath boundaries and its volume fraction also increases with the increase of the aging temperature. At the same time, the size of the Cu precipitates gradually increases. Compared with the traditional single aging and double aging treatment, double aging treatment of 15-5PH stainless steel can increase the toughness while retaining the necessary strength. During double aging of 550 ℃ × 4 h + 580 ℃ × 1 h, 15-5PH stainless steel has the best strength and low-temperature (- 40 ℃) toughness match. Its yield strength, ultimate tensile strength and the Charpy impact energy are 1.037 GPa, 1.086 GPa and 179 J, respectively. Reference | Related Articles | Metrics

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Improvement of Physical Fitness Test Assessment Criteria Based on fNIRS Technology: Taking Pull-Up as an Example GONG Bin(巩斌), YU Xianghua(禹香华), FANG Yu (方宇), WANG Zheng (王正), YANG Hao (杨皓), CHEN Guodong (陈国栋), L Ü Na (吕娜) J Shanghai Jiaotong Univ Sci    2022, 27 (2): 219-225.   DOI: 10.1007/s12204-021-2367-4 Abstract （213）      PDF （1855KB）（82）       Knowledge map    Pull-up, as an important physical fitness test event of the “National Student Physical Health Standard”, is known as a difficult physical fitness test event. To improve the assessment criteria of pull-ups, this paper uses the functional near-infrared spectroscopy (fNIRS) to monitor the changes and activation of oxyhemoglobin (HbO) signals in the brain motor cortex of people with different body mass indexes (BMIs) during the pullup assessment. Then the relationship between BMIs and evaluation criteria is discussed. After collecting and analyzing experimental data of 18 recruited college students, it is found that the number of pull-ups performed by people with different BMIs is different when they reach the peak state of brain activation. The results of the study indicate that different assessment criteria should be adopted for different BMI groups. It is suggested that the BMI should be introduced as one of the test indexes in the examination of pull-ups event in “National Student Physical Health Standard”. Reference | Related Articles | Metrics

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Birds-Eye-View Semantic Segmentation and Voxels Semantic Segmentation Based on Frustum Voxels Modeling and Monocular Camera QIN Chao1 (秦 超), WANG Yafei1 (王亚飞), ZHANG Yuchao2 (张宇超), YIN Chengliang1∗ (殷承良) J Shanghai Jiaotong Univ Sci    2023, 28 (1): 100-113.   DOI: 10.1007/s12204-023-2573-3 Abstract （174）      PDF （3885KB）（55）       Knowledge map    The semantic segmentation of a bird’s-eye view (BEV) is crucial for environment perception in autonomous driving, which includes the static elements of the scene, such as drivable areas, and dynamic elements such as cars. This paper proposes an end-to-end deep learning architecture based on 3D convolution to predict the semantic segmentation of a BEV, as well as voxel semantic segmentation, from monocular images. The voxelization of scenes and feature transformation from the perspective space to camera space are the key approaches of this model to boost the prediction accuracy. The effectiveness of the proposed method was demonstrated by training and evaluating the model on the NuScenes dataset. A comparison with other state-of-the-art methods showed that the proposed approach outperformed other approaches in the semantic segmentation of a BEV. It also implements voxel semantic segmentation, which cannot be achieved by the state-of-the-art methods. Reference | Related Articles | Metrics