Research on MBSE Application for Radio Navigation System

The rapid development of concepts and technologies for civil aircraft navigation systems has put forward higher requirements for agile iteration and integrated design verification in the research and development(R&D)process.Traditional document based system engineering(DBSE)methods have gradually become inadequate.Model based system engineering(MBSE)is fully based on user′s needs and is carried out from top to bottom,in line with the concept of forward design.It is gradually being applied in the development of civil aircraft systems.This article focuses on the civil aircraft radio navigation system and proposes a complete system engineering solution based on models,from system design and development to validation.Guided by the Arcadia methodology,with Capella modeling tool,Simulink simulation tool,and system validation tool,the complete R&D process from design and development to testing and validation was achieved through model construction,code generation,and testing validation.A radio navigation station selection optimization method based on machine learning was proposed,and results had good signal quality and persistence.The verification result of Beijing⁃Shanghai flight route shows MBSE method practiced in this article can ensure the feasibility of the entire process of radio navigation system development,as well as the rationality of tuning and positioning result.By automatically generating code to form a universal functional module,an optimization method that integrates different radio navigation station selection strategies is achieved,providing new ideas for the development and design of radio navigation systems.

文明1(civilized)、文明2(civilization)、文明3(civitas)——论“文明”一词的三种不同含义

学术界对于“什么是文明”存有争议的原因,是把文明(civilized)、文明社会(civilization)和国家(civitas)三个不同的概念混为一谈造成的。“文明1”大致相当于英语civilized(文明的)。文化是人群的生活方式,但是不仅彬彬有礼、琴棋书画、轻歌曼舞、美味佳肴是文化,愚昧粗鲁、恶俗陋习、野风蛮舞、吃糠咽菜也是生活方式,所以文明1不完全等同于文化,而只有被认可与受推崇的文化才被称为文明。无论古今中外,作为文化的文明1都是褒义的,文明1即“文明”的本义,也是对文化的价值判断。“文明2”相当于英语civilization(文明社会),摩尔根用以指称继蒙昧社会与野蛮社会之后出现的、高于蒙昧与野蛮状态的社会阶段。作为社会形态的文明2当然比蒙昧与野蛮社会要进步,但是文明社会并非一切都是文明的,其中充斥着种种不文明的蒙昧与野蛮,所以不能说文明2就是“文明的”社会。“文明3”相当于英语civitas(国家),是中国学者根据恩格斯的“国家是文明社会的概括”得出的概念,系指继部落联盟或酋邦之后出现的社会组织形态。因为不同国家的国体与政体各不相同,有了国家之后并非一切都变得比野蛮社会更文明了,所以作为国家的文明3也不都是“文明的”国家。

Civil3d技术在河道治理中的应用分析

为了切实加强水环境保护及水资源管理与利用,近年来我国一直在加快和加大力度落实河道治理,要想保证河道治理达到预期效果,并最大程度提高河道治理工程生态效益,首先要确保河道治理设计与施工方案的科学合理性,可见借助现代化技术手段,优化和改进河道治理设计与规划是很有必要的。基于此本文首先进行Civil3d技术的梳理与说明,继而详细分析Civil3D软件在某河道治理项目的具体应用,旨在与相关工作人员相互交流、共同探讨。

Utilization of Basalt Saw Mud as a Spherical Porous Functional Aggregate for the Preparation of Ordinary Structure Concrete

To promote the production and application of artificial aggregates,save natural sand resources and protect the ecological environment,we evaluated the feasibility of using spherical porous functional aggregates(SPFAs) formed by basalt saw mud under autoclave curing in ordinary structural concrete.In our work,two types of prewetted functional aggregates were taken as replacements for natural aggregates with different volume substitution rates(0%,5%,10%,15%,20%,25%,and 30%) in the preparation of ordinary structural concrete with water-to-binder ratios(W/B) of 0.48 and 0.33.The effects of the functional aggregate properties and content,W/B,and curing age on the fluidity,density,mechanical properties and autogenous shrinkage of ordinary concrete were analyzed.The experimental results showed that the density of concrete declined at a rate of not more than 5%,and the 28 d compressive strength could reach 31.0-68.2 MPa.Low W/B,long curing age and high-quality functional aggregates were conducive to enhancing the mechanical properties of SPFAs concrete.Through the rolling effects,SPFAs can optimize the particle gradation of aggregate systems and improve the fluidity of concrete,and the water stored inside SPFAs provides an internal curing effect,which prolongs the cement hydration process and considerably reduces the autogenous shrinkage of concrete.SPFAs exhibits high strength and high density,as well as being more cost-effective and ecological,and is expected to be widely employed in ordinary structural concrete.

Study on The Ecology System of Hani Terraced Paddy Fields

The ecology system of Hani Terraced Paddy Fields is the typical repre-sentative of the ecological agriculture in the southwestern mountainous areas of our country. After long-term development, Hani ecology system has developed, cored by＂forest-vil age-terrace-river＂, including paddy cultivation system, forests and ecologi-cal maintenance, folk culture and construction of water facilities. This research ex-plored the details of the structure and functions of the ecology system of Hani ter-raced fields. And il ustrates that the system is a new model of agriculture ecological civilization and deserves further study and more applications.

基于移动端的水工建筑物轻量化模型展示研究

针对三维水工建筑物模型在电脑端使用中存在交互能力受限、便携性差等问题,以提高水工建筑物信息化程度为目标,搭建了一个以移动端为主的三维模型展示平台,以满足水工建筑物模型在实际工程和研究中的需求。平台基于微信小程序云端与Cesium组合而成,整体研发分为3个步骤:首先是结合Revit与Civil 3D两类建模软件各自优势完成参数化建模;之后利用Cesium平台对模型纹理、数据、材质等进行压缩,完成模型的轻量化处理;最后通过云函数引用微信小程序云端中的模型,将三维模型展示在移动端,以此实现三维模型与微信小程序结合,旨在克服传统展示方式的局限性,为用户提供更加便捷、沉浸式的体验。

BIM技术在市政道路设计中的应用研究

为提高市政道路设计水平,总结了BIM技术的应用特点和实现方式,以某城市快速路为研究对象,探讨了Civil 3D软件在市政道路平纵线形设计、横断面装配、土石方计算、三维视距计算、碰撞检测、驾驶模拟等方面的具体应用,研究成果可为推动市政道路设计的转型和升级提供理论指导。

How far have we come?Review of main public policies to reduce landslide impacts in Brazil

During the rainy season in Brazil,landslides can have catastrophic consequences,including loss of life,damage to urban infrastructure and significant economic impacts.Now,more than eight million people in Brazil live in disaster-prone areas.The objective of this article is to present a chronological review of the principal policies and programmes at the national,state,and municipal levels,with an emphasis on their key actions aimed at mitigating the impact of disasters related to natural hazards,particularly landslides.Our analysis was based on official records of public policies from the national,state,and municipal governments.The results show that several initiatives were initially developed at the local and regional level.However,it was not until the late 1980s that a comprehensive organisation of civil protection at the national level emerged as a response measure.It is possible to highlight three phases(understanding,coexistence,and prevention)of institutional action focused on risk management in the face of disasters.Despite the growing knowledge of risk scenarios,disasters continue to occur in Brazil on an annual basis,revealing several obstacles to reducing their impact,particularly given the social and economic disparities between Brazilian regions and the applicability of public policies that must overcome the limitations of each municipality.

矮塔斜拉桥双肢薄壁墩0#块托架M型反力架预压技术研究

以渠江特大斜拉桥双肢薄壁墩0#块托架预压施工为研究背景,设计并提出了一种M型反力架,并采用Midas Civil建立有限元模型,对预压施工过程中M型反力架的受力和变形进行计算分析。研究表明,预压荷载作用下M型反力架的受力和变形均满足设计要求,表明该型反力架可有效保障双肢薄壁墩0#块托架预压施工的顺利进行。同时,有限元数值计算可有效应用于相关预压施工的反力架设计中。

Anti-Spoofing:Integrated Information Authentication of BeiDou-ⅡCivil Navigation Message

The BeiDou-Ⅱcivil navigation message(BDⅡ-CNAV)is transmitted in an open environment and no information integrity protection measures are provided.Hence,the BDⅡ-CNAV faces the threat of spoofing attacks,which can lead to wrong location reports and time indication.In order to deal with this threat,we proposed a scheme of anti-spoofing for BDⅡ-CNAV based on integrated information authentication.This scheme generates two type authentication information,one is authentication code information(ACI),which is applied to confirm the authenticity and reliability of satellite time information,and the other is signature information,which is used to authenticate the integrity of satellite location information and other information.Both authentication information is designed to embed into the reserved bits in BDⅡ-CNAV without changing the frame structure.In order to avoid authentication failure caused by public key error or key error,the key or public key prompt information(KPKPI)are designed to remind the receiver to update both keys in time.Experimental results indicate that the scheme can successfully detect spoofing attacks,and the authentication delay is less than 1%of the transmission delay,which meets the requirements of BDⅡ-CNAV information authentication.

Design and implementation of the simulation system for GPS new civil signals

In order to research on the design and implementation of a modernized GPS civil signals simulation system,a brief review of the modernized GPS signals is introduced,including the signal structure and characteristics of L2C,L5 and L1C signals.The design and implementation of the main modules of the simulation system is described in detail.The simulation system is mainly composed of parameter setting,system initialization,signal generator,noise generator,disturbance generator,signal synthesis,low-pass filter,A/D conversion and storage.The simulation results based on Matlab are then presented,and the power spectral density（PSD） of all navigation signals is analyzed.The simulation system completes the physical layer simulation of a modernized GPS new civil signal and can provide a controllable signal source for designing and testing of modernized GPS civil receivers,especially for the signal processing algorithm design of the GPS software receiver.

Predictive maintenance and its applications in civil engineering structures:A review

Structural health monitoring and performance prediction are crucial for smart disaster mitigation and intelligent management of structures throughout their lifespan.Recent advancements in predictive maintenance strategies within the industrial manufacturing industry have inspired similar innovations in civil engineering,aiming to improve structural performance evaluation,damage diagnosis,and capacity prediction.This review delves into the framework of predictive maintenance and examines various existing solutions,focusing on critical areas such as data acquisition,condition monitoring,damage prognosis,and maintenance planning.Results from real-world applications of predictive maintenance in civil engineering,covering high-rise structures,deep foundation pits,and other infrastructure,are presented.The challenges of implementing predictive maintenance in civil engineering structures under current technology,such as model interpretability of data-driven methods and standards for predictive maintenance,are explored.Future research prospects within this area are also discussed.

圆竹-钢组合拱桥变形控制关键技术

为探究圆竹-钢组合拱桥拱圈等部位的变形控制技术,以武夷山玲珑大桥为研究对象,通过Midas Civil软件建立模型,分析其在设计阶段,不同荷载组合下,不同的桥面系、拱圈截面、横向连接和拱脚连接方式下的拱圈竖向与横向位移。结果表明:采用组合桥面系、横向连接以及提高拱圈与拱脚的刚度能在一定程度上减少拱圈等部位的变形。为更有效地控制变形,还需要结合实际施工过程中的变形控制技术和软件对各个施工阶段的模拟。综合应用设计阶段的分析和施工阶段中的变形控制技术,可以有效预防和控制圆竹-钢组合拱桥的变形问题,确保结构的安全性和稳定性。研究结果可为其他类似圆竹结构工程的建设提供参考。

Research on Improving Artistry of Exhibitions in History Museums in China

Chinese civilization,with its long and continuous history and rich cultural heritage,plays a central role in China’s dialogue with other civilizations.Therefore,it is necessary to collect and refine the defining symbols and best elements of Chinese culture and showcase them to the world;develop discourse and narrative systems with Chinese characteristics,better tell China’s stories,and make China’s voice heard.This effort can help Chinese civilization shine globally,interact with other civilizations,and promote its communication and influence worldwide.In China,history museums,as physical carriers of Chinese civilization,are an important component in developing Chinese discourse and narrative systems and an important channel to better tell China’s stories and make China’s voice heard.Improving the artistry of museum exhibitions caters to the public’s growing demand for a more enriching cultural experience and substantially promotes Chinese culture on a global scale.With the communication of Chinese civilization as the main focal point,this study investigated the current issues related to the artistry of history museum exhibitions in China and defined the artistry of history museum exhibitions and their connotations.Based on an in-depth analysis of the artistry of historical museum exhibitions within China,this paper enumerated the areas where improvements could be made to enhance exhibition artistry,intending to promote the communication of Chinese civilization.

BDSec:Security Authentication Protocol for BeiDou-Ⅱ Civil Navigation Message

Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-Ⅱ civil navigation message(BDⅡ-CNAV) are vulnerable to spoofing attack and replay attack.To solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM) series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)algorithm.In BDSec protocol,both of BDⅡ-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication information.BDSec protocol applies SM9 algorithm(Identity-based cryptography mechanism) to protect the integrity of the BDⅡ-CNAV,adopts the SM2 algorithm(Public key cryptosystem) to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm) to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol respectively.The results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDⅡ-CNAV.

Exploring the Applications of Digital Twin Technology in Enhancing Sustainability in Civil Engineering:A Review

With the advent of the big data era and the rise of Industrial Revolution 4.0,digital twins(DTs)have gained sig-nificant attention in various industries.DTs offer the opportunity to combine the physical and digital worlds and aid the digital transformation of the civil engineering industry.In this paper,605 documents obtained from the search werefirst analysed using CiteSpace for literature visualisation,and an author co-occurrence network,a keyword co-occurrence network,and a keyword clustering set were obtained.Next,through a literature review of 86 papers,this paper summarises the current status of DT application in civil engineering based on a review of the origins,concepts,and implementation techniques of DTs,and it introduces the application of DTs in the full project lifecycle.This study shows that DTs have great potential to address many of the challenges faced by civil engineering.In this regard,the paper also presents some thoughts on the future directions of DT research.

Association between Mental Health Literacy and Workplace Well-Being of Chinese Grassroots Civil Servants:The Chain Mediating Effects of Regulatory Emotional Self-Efficacy and Resilience

This study aimed to investigate the relationship between mental health literacy(MHL)and workplace well-being(WWB)of Chinese grassroots civil servants,with regulatory emotional self-efficacy(RESE)and resilience as mediating variables.A questionnaire survey was conducted among Chinese grassroots civil servants,with a valid sample size of 2673 after excluding missing values and conducting relevant data processing.The PROCESS was used to examine the relationship between MHL,RESE,resilience,and WWB.The study found that MHL among grassroots civil servants was positively and significantly correlated with WWB(r=0.73,p<0.01).RESE partially mediated the relationship between MHL and WWB(β=0.25,95%CI[0.22,0.28]).Resilience partially mediated the relationship between MHL and WWB(β=0.22,95%CI[0.19,0.26]).MHL had a positive effect on WWB through the chain mediating effect of RESE and resilience(β=0.05,95%CI[0.03,0.07]).There is a close relationship between MHL and WWB,where Chinese grassroots civil servants with higher levels of MHL can develop stronger RESE and resilience,leading to higher WWB.The results of this study remind organizational institutions of Chinese grassroots civil servants that enhancing MHL,RESE,and resilience is an important pathway to promoting their WWB.

Understanding Chinese Civilisation from the Perspective of Cultural Relics

At a meeting on cultural inheritance and development on June 2,2023,President Xi Jinping summarised with penetrating insight the distinctive features of Chinese civilisation and elucidated the significance of the“two integrations”(integrating the basic tenets of Marxism with China's specific realities and the best of its traditional culture),which explain the development laws underlying Chinese civilisation.This reflects the new heights the Communist Party of China(CPC)has attained in its understanding of the path,theory,and system of socialism with Chinese characteristics,in its confidence in Chinese history and culture,and in its consciousness of promoting cultural innovation while carrying forward the traditional Chinese culture.

Speech at the Civilisation Lecture by Svetlana Sharenkova,Vice-President of Bulgaria-China Forum(Abstract)

When we try to talk about civilisation exchanges and mutual learning between China and Bulgaria,it's easy and difficult.China boasts the most ancient civilisation in the world with an ever-lasting history of over 5000 years.With a history of over 1300 years,Bulgaria is one of the oldest civilisations in Europe.There are three major civilisations emerging and thriving on this very land.

Understanding the Laws Underlying the Development of Chinese Civilisation

At a meeting on cultural inheritance and development held in Beijing,June 2,2023,President Xi Jinping put forward a holistic and systematic explanation of the distinctive features of Chinese civilisation-consistency,originality,unity,inclusiveness,and a peaceful nature.President Xi Jinping's profound exposition has granted us a deeper understanding of the laws underlying the development of Chinese civilisation by shedding light on its intrinsic characteristics.