Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University最新文献

{"title":"Unsupervised 3D reconstruction method based on multi-view propagation","authors":"Jingfeng Luo, Dongli Yuan, Lan Zhang, Yaohong Qu, Shihong Su","doi":"10.1051/jnwpu/20244210129","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210129","url":null,"abstract":"In this paper, an end-to-end deep learning framework for reconstructing 3D models by computing depth maps from multiple views is proposed. An unsupervised 3D reconstruction method based on multi-view propagation is introduced, which addresses the issues of large GPU memory consumption caused by most current research methods using 3D convolution for 3D cost volume regularization and regression to obtain the initial depth map, as well as the difficulty in obtaining true depth values in supervised methods due to device limitations. The method is inspired by the Patchmatch algorithm, and the depth is divided into n layers within the depth range to obtain depth hypotheses through multi-view propagation. What's more, a multi-metric loss function is constructed based on luminosity consistency, structural similarity, and depth smoothness between multiple views to serve as a supervisory signal for learning depth predictions in the network. The experimental results show our proposed method has a very competitive performance and generalization on the DTU, Tanks & Temples and our self-made dataset; Specifically, it is at least 1.7 times faster and requires more than 75% less memory than the method that utilizes 3D cost volume regularization.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"231 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140466775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Friction compensation control of pneumatic position servo system based on the adjustable stiffness","authors":"Qiong Wei, Hao Lu, Zilong Wu, Linyong Bai, Daode Zhang, Yi Li","doi":"10.1051/jnwpu/20244210138","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210138","url":null,"abstract":"Due to the characteristics of low stiffness, low air source pressure, and easy fluid saturation of the pneumatic servo system, the energy dissipation of the system during the working process is large, the system is easily affected by friction, and the compensation effect is not obvious. Especially, the \"Flat roof phenomenon\" will become stronger when changing the speed direction. It seriously affects the tracking accuracy of the pneumatic servo system. In this paper, the independent metering valve control structure is proposed to eliminate the energy dissipation caused by the coupling of two chambers, so that the air fluid characteristics are within the linear range as far as possible. The nonlinear adaptive robust control method is designed for the uncertainty of some parameters in the friction, external disturbances, and dynamic loads in the pneumatic system. At the same time, the stiffness adjustment and adaptive robust control of the system are coordinated to improve the dynamic performance of the pneumatic position servo system. The simulation and experimental results show that the adaptive robust controller with stiffness adjustment can effectively reduce the energy dissipation of the system, improve the position tracking accuracy of the system, and weaken the \"Flat roof phenomenon\" caused by friction.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"349 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140468481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a novel wastewater reuse system for space station based on urea electrooxidation technology","authors":"Lu Wang, Ke Zhang, Lijie Yuan, Jiayu Guo, Yanni Tian","doi":"10.1051/jnwpu/20244210173","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210173","url":null,"abstract":"The replenishment of water resources in a space station is essential for achieving an astronaut's long-term and on-orbit residence. Recycling his or her urine is one of important and major ways of wastewater recovery. However, traditional urine treatment methods have the disadvantages of equipment that takes large space, complex procedures and low atomic utilization. Therefore, this paper designs a novel wastewater reuse system that treats urine based on urea electrooxidation technology, introduces methane fuel cell coupled with the Sabatier reactor and hydrogen-oxygen fuel cell to further utilize urine treatment products and to allocate water resources precisely in the space station through designing grading treatment and dynamic control systems. The wastewater reuse system designed in the paper contributes to saving valuable space and reducing energy consumption during urine treatment, thus improving water recovery rate and optimizing resource allocation.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"384 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140466390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation on hydrodynamics loads during tail rudder deployment procedure of supercavitating vehicle","authors":"Zhong Wang, Menghao Wang, Yuanming Peng, Rui Lu, Jingjun Zhou","doi":"10.1051/jnwpu/20244210028","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210028","url":null,"abstract":"In the state of navigating covered with liquid fluid, the hydrodynamics loads of the supercavitating vehicle during the deployment process of the tail rudder have an important impact on the stability analysis of the vehicle and the performance design of the tail rudder. In this study, a numerical simulation method for the deployment process of the rudder based on the overlapping grids technology and the concept of relative motion between grid domains is established. Combined with the design requirements of the supercavitating vehicle, the change law of hydrodynamics loads under different deployment rates, attack angles during the deployment process, before and after deployment of the tail rudder are researched in detail. Through the analysis of the velocity vector field, pressure field near the rudder and pressure coefficients of the rudder surface, the reasons for the changes of the hydrodynamic loads in different states are revealed. The results have important reference value for the research on the flow field characteristics of the deployment process of the tail rudder for the supercavitating vehicle, and provide an important design basis for the performance design of the tail rudder.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"773 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140467953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on preparation of electrically grafted dicyandiamide modified carbon fibre electrode for marine electric field and its electric field response performance","authors":"Jiawei Xu, Chengru Hu, Xiaofan Hou, Yubin Fu","doi":"10.1051/jnwpu/20244210180","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210180","url":null,"abstract":"Surface amino modification of carbon fibre electrodes can significantly improve their electrochemical and electric field response properties. In this paper, we tune up the grafting voltage (3, 5, 7 V) and graft polyaminocyanine films on the surface of carbon fibres to modulate the structure and electrochemical properties of the electric double layer at the electrode/sea water interface. The results show that the higher the grafting potential, the more uniform the polyaminocyanine film on the carbon fibre surface and the more stable the electrode bilayer structure. The CF-7V has the best overall performance with a specific capacitance of 9.368 F·g-1, 31.6 times that of the blank group; the charge transfer resistance and low frequency capacitive resistance are significantly reduced; the 7-day potential drift is 1.68 mV, which can respond normally to low frequency weak electric field signals at 1 mHz and 0.03 mV/m, and the response sensitivity and accuracy of the electrodes have been significantly improved. The electric field response performance of the electrically grafted modified carbon fibre electrode is comparable to that of the Ag/AgCl electrode. This is a new type of high performance marine electric field sensor, which is expected to improve the detection capability of marine electric fields.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"262 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140468032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on game strategy of spacecraft chase and escape based on adaptive augmented random search","authors":"Jie Jiao, Yongjie Gou, Wenbo Wu, Binfeng Pan","doi":"10.1051/jnwpu/20244210117","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210117","url":null,"abstract":"To solve the problem of the survival differential policy interception between a spacecraft and a non-cooperative target pursuit game, the pursuit game policy is studied based on reinforcement learning, and the adaptive-augmented random search algorithm is proposed. Firstly, to solve the sparse reward problem of sequential decision making, an exploration method based on the spatial perturbation of parameters of the policy is designed, thus accelerating its convergence speed. Secondly, to avoid the possibility of falling into local optimum prematurely, a novelty degree function is designed to guide the policy update, enhancing the efficiency of data utilization. Finally, the effectiveness and advancement of the exploration method are verified with numerical simulations and compared with those of the augmented random search algorithm, the proximal policy optimization algorithm and the deep deterministic policy gradient algorithm.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"279 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140468737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyzing cavity evolution and motion characteristics of asynchronous parallel oblique water-entry super-cavitating projectile","authors":"C. Gao, Lin Lu, Xiaobin QI, Xu Yan, Chen Wang, Yanxiao Hu, Dongxia Zhang","doi":"10.1051/jnwpu/20244210018","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210018","url":null,"abstract":"Based on the volume of fluid multiphase flow model and the overset mesh technique, a numerical method for an asynchronous parallel oblique water-entry super-cavitating projectile was established. Experimental studies of the oblique water-entry of a high-speed single-launch projectile were carried out to validate the viability of the numerical method. The paper performed the numerical simulations and analyses of cavity evolution and motion characteristics of the front and rear projectiles in different initial intervals and in two sequences of top-side water-entry projectile first and bottom-side water-entry projectile first. The results show that when the initial interval of the first launch projectile is 0.5 time the projectile length, the first launch projectile cannot produce a cavity to completely encapsulate the projectile due to the violent squeezing of the following launch projectile cavity, and its movement is seriously affected and eventually loses its trajectory stability. At the same time, the first launch projectile that enters water from top side is squeezed to a larger degree than the one from bottom side, and the wetting phenomenon occurs earlier and loses stability faster. As the initial interval increases, the influence of the following launch projectile cavity near the first launch projectile is weakened, and the first launch projectile in both water entry sequences move steadily. For the following launch projectile, due to the continuous influence of the first launch projectile cavity, its cavity is always asymmetrical, and its motion stability is affected. The following launch projectile deflects to the inner side and destabilizes when the initial interval is 0.5 times the projectile length. When the initial interval is 1 time the projectile length, it moves steadily. It deflects to the outer side and destabilizes when the initial interval is 2 and 3 times the projectile length. In addition, the motion characteristics of the following launch projectile are basically identical in two water-entry sequences.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"133 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140470494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Safety assessment of virtualization computing platform for avionics system of civil aircraft","authors":"Huan Yang, Xiaodong Wang, Geng Li, Shuang Zhang, Yangming Guo","doi":"10.1051/jnwpu/20244210045","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210045","url":null,"abstract":"Aiming at the main problems that affect the security of airborne computing platform after virtualization, such as time-space isolation, fault isolation and schedulability, this paper studies the security level evaluation of airborne computing platform under virtualization environment. Considering the characteristics of virtualized avionics system, a security calculation method based on analytic hierarchy process(AHP) and gray correlation analysis(GARD) is proposed. The safety evaluation decision tree of airborne virtualization computing platform is established, and the weight of each safety capability is calculated by AHP method, and the overall safety score of the system is given. On this basis, combined with GRAP method and referring to the safety evaluation of avionics system, the safety level with the highest adaptability between the test system and DAL safety level requirements is calculated, realizing security grade evaluation of airborne computing platform under virtualization environment.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"43 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140464693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Harmony SE in civil aircraft design","authors":"Wanyi Liu, Yunwen Feng, Jieran Hou, Junyu Chen, Yingnan Guo","doi":"10.1051/jnwpu/20244210035","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210035","url":null,"abstract":"With the refinement of civil aircraft technology and the enhancement of product complexity, civil aircraft design has changed from traditional text-based system engineering to model-based system engineering, the expression of the system has also transformed from text-centered to model-centered. To further improve the model quality and correctness of aircraft system modeling, this paper explores the applicability of model-driven and verification-oriented system engineering methods in the field of civil aircraft design, and establishes the system engineering practice framework of civil aircraft design, which can ensure the rapid design and efficient delivery of civil aircraft. Firstly, starting from the Harmony SE modeling method, the workflow and modeling ideas of system are introduced; then the noticeable problems in the practice of civil aircraft system engineering are analyzed, and the system engineering practice of civil aircraft design is established with the support of the applicability of the Harmony SE method; finally, the fuel tank pressurization component is taken as the research object of the practice system in component-level. The results show that the system engineering practice framework of civil aircraft design and method proposed in this paper can correctly and reasonably allocate design requirements and establish a complete system model, which is helpful to improve the efficiency and accuracy of civil aircraft design at this stage.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140464697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cross-lingual entity alignment method based on attribute weight updating network","authors":"Zhehan Su, Tao Xu, Yugang Dai, Yujia Liu","doi":"10.1051/jnwpu/20244210157","DOIUrl":"https://doi.org/10.1051/jnwpu/20244210157","url":null,"abstract":"Due to the large number of attributes and the low repetition rate in a cross-lingual knowledge graph, it is difficult for an alignment task to embed attribute information efficiently. To solve the problem, an entity alignment model based on attribute weight updating network was proposed. Firstly, in order to embed attribute information efficiently, attribute embedding is approximately constructed with entity embedding through a constructor, thus avoiding their separate training. Secondly, based on the fact that different attributes make different contributions to entity alignment, an attribute weight updating module based on graph attention network was proposed to update the weight of each attribute through using attention scores in the process of training. Finally, attribute embedding and attribute weight information were aggregated into entity embedding with an attribute aggregation module to strengthen the representation of entity embedding and improve the entity alignment performance. The experimental results show that the proposed model achieves 0.751, 0.805 and 0.915 scores respectively from the Hits@1 score in three cross-lingual datasets. Its alignment performance is better than that of the current mainstream entity alignment method.","PeriodicalId":515230,"journal":{"name":"Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University","volume":"265 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140469738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}