Review of Power Supply and Distribution Construction Technology for Highway Electromechanical Engineering

In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expansion of highway construction,power supply,and distribution has led to several challenges in mechanical and electrical engineering technology.Ensuring the safe,stable,and cost-effective operation of the power supply and distribution system to meet the diverse requirements of highway operations has become a pressing issue.This article takes an example of a highway electromechanical engineering power supply and distribution construction project to provide insight into the construction process of highway electromechanical engineering power supply and distribution technology.

International Standardization of Blockchain and Distributed Ledger Technology:Overlaps,Gaps and Challenges

As one of the most concerned digital technologies in recent years,blockchain and distributed ledger technology are an important driving force for a new round of technological development.It is currently in the process of accelerating its evolution and maturity,and has gradually integrated with other digital technologies.It has been applied in many industries,providing decentralized solutions for various industries,realizing innovative storage models,and building a new trust system.As blockchain technology is officially incorporated into China’s new information infrastructure category,the application fields of blockchain have expanded rapidly,gradually extending from the financial field and government affairs to other fields in the real economy.At the same time,with the continuous development of the globalized economy,blockchain technology will also have a profound impact on international technological and economic development.Therefore,for the healthy and orderly development and real implementation of the blockchain industry,standardize the application of blockchain,effectively break through the cognitive and technical barriers between different countries,industries and systems on a global scale,prevent application risks,the development of the global blockchain industry needs standardization basis,which is particularly important and urgent.A sound standard system is an important key to the successful development of technology,and formulating the right standard at the right time for technology development helps ensure the ease of use and interoperability of the technology.From the perspective of international standardization,this article first introduces the general situation of ISO,ITU-T,IEEE,W3C and other international standardization organizations,and sorts out the status quo of the blockchain standardization working groups of mainstream international standardization organizations.All blockchain-related standards under development have been analyzed for the characteristics of international blockchain technology standards and industry application standards.Through data analysis,the overlaps,differences and conflicts in the field of international blockchain standard formulation are sorted out,and suggestions for blockchain standardization work in the application and development of blockchain technology standardization by international organizations and industries are put forward.The plans and layouts of future international standards are summarized to help the development of the international standardization of blockchain.

Distributed ledger technology for securities clearing and settlement: benefits, risks, and regulatory implications

This article outlines the benefits and risks of the distributed ledger technology(DLT)for the clearing and settlement of exchange-traded and OTC securities,followed by a description of the technology’s potential role for central counterparties and central securities depositories.Although the industry and scholars are attempting to solve the technological and operational issues that DLT systems still face,outstanding legal risks are such that the financial industry is asking for more regulatory guidance and intervention.This article wants to contribute to the public policy debate by presenting potential regulatory barriers that may have to be removed for DLT to be fully adopted.In addition,it identifies areas requiring an update of the legal framework in order to address certain prudential and conduct risks that this technology could introduce.

Privacy-preserving analytics for the securitization market: a zero-knowledge distributed ledger technology application

A zero-knowledge proof or protocol is a cryptographic technique for verifying private data without revealing it in its clear form.In this paper,we evaluate the potential for zero-knowledge distributed ledger technology to alleviate asymmetry of information in the asset-backed securitization market.To frame this inquiry,we conducted market data analyses,a review of prior literature,stakeholder interviews with investors,originators and security issuers and collaboration with blockchain engineers and researchers.We introduce a new system which could enable all market participants in the securitization lifecycle(e.g.investors,rating agencies,regulators and security issuers)to interact on a unique decentralized platform while maintaining the privacy of loan-level data,therefore providing the industry with timely analytics and performance data.Our platform is powered by zkLedger(Narula et al.2018),a zero-knowledge protocol developed by the MIT Media Lab and the first system that enables participants of a distributed ledger to run publicly verifiable analytics on masked data.

Twin-Field Quantum Key Distribution Protocol Based on Wavelength-Division-Multiplexing Technology

Quantum key distribution(QKD) generates information-theoretical secret keys between two parties based on the physical laws of quantum mechanics. Following the advancement in quantum communication networks, it becomes feasible and economical to combine QKD with classical optical communication through the same fiber using dense wavelength division multiplexing(DWDM) technology. This study proposes a detailed scheme of TF-QKD protocol with DWDM technology and analyzes its performance, considering the influence of quantum channel number and adjacent quantum crosstalk on the secret key rates. The simulation results show that the scheme further increases the secret key rate of TF-QKD and its variants. Therefore, this scheme provides a method for improving the secret key rate for practical quantum networks.

Fabrication of 32 Gb/s Electroabsorption Modulated Distributed Feedback Lasers by Selective Area Growth Technology

A 32 Gb/s monolithically integrated electroabsorption modulated laser is fabricated by selective area growth technology. The threshold current of the device is below 13mA. The output power exceeds 10mW at 0V bias when the injection current of the distributed feedback laser is 100mA at 25℃. The side mode suppression ratio is over 50 dB. A 32Gb/s eye diagram is measured with a 3.SVpp nonreturn-to-zero pseudorandom modulation signal at -2.3 V bias. A clearly opening eyediagram with a dynamic extinction ratio of 8.01 dB is obtained.

Comparison of Temperature Field Distribution between Cement Preclinkering Technology and Cement Precalcining Technology

Through the comparison of calcination conditions between cement preclinkering technology and cement precalcining technology,we studied the characteristics of temperature field distribution of cement preclinkering technology systems including cyclone preheater,preclinkering furnace,and rotary kiln.We used numericalsimulation method to obtain data of temperature field distribution.Some results are found by system study.The ratio of tailcoalof cement preclinkering technology is about 70%,and raw mealtemperature can reach 1070 ℃.Shorter L/D kiln type of preclinkering technology can obtain more stable calcining zone temperature.The highest solid temperature of cement preclinkering technology is higher than 80 ℃,and high temperature region（〉1450 ℃）length is 2 times,which is beneficialfor calcining clinker and higher clinker quality.So cement preclinkering technology can obtain more performance temperature filed,which improves both the solid-phase reaction and liquid-phase reaction.

Markets in crypto‑assets regulation:Does it provide legal certainty and increase adoption of crypto‑assets?

This study discusses the European Union’s proposal for a Regulation on Markets in Crypto-Assets,now subject to formal approval by the European Parliament.The objective is to explore whether it will positively impact the adoption of crypto-assets in the financial sector.The use of crypto-assets is growing.However,some stakeholders in the financial service sector remain skeptical and hesitant to adopt assets that are yet to be defined and have an unclear legal status.This regulatory uncertainty has been identified as the primary reason for the reluctant adoption.The proposed regulation(part of the EU’s Digital Finance Strategy)aims to provide this legal certainty for currently unregulated crypto-assets.This study investigates whether or not the proposed regulation can be expected to have the intended effect by reviewing the proposed regulation itself,the opinions and reactions of the various stakeholders,and secondary literature.Findings reveal that such regulation will most likely not accelerate the adoption of crypto-assets in the EU financial services sector,at least not sufficiently or as intended.Some suggestions are made to improve the proposal.

Blockchain and IIoT Enabled Solution for Social Distancing and Isolation Management to Prevent Pandemics

Pandemics have always been a nightmare for humanity,especially in developing countries.Forced lockdowns are considered one of the effective ways to deal with spreading such pandemics.Still,developing countries cannot afford such solutions because these may severely damage the country’s econ-omy.Therefore,this study presents the proactive technological mechanisms for business organizations to run their standard business processes during pandemic-like situations smoothly.The novelty of this study is to provide a state-of-the-art solution to prevent pandemics using industrial internet of things(IIoT)and blockchain-enabled technologies.Compared to existing studies,the immutable and tamper-proof contact tracing and quarantine management solution is proposed.The use of advanced technologies and information security is a critical area for practitioners in the internet of things(IoT)and corresponding solutions.Therefore,this study also emphasizes information security,end-to-end solution,and experimental results.Firstly,a wearable wristband is proposed,incorporating 4G-enabled ultra-wideband(UWB)technology for smart contact tracing mechanisms in industries to comply with standard operating procedures outlined by the world health organization(WHO).Secondly,distributed ledger technology(DLT)omits the centralized dependency for transmitting contact tracing data.Thirdly,a privacy-preserving tracing mechanism is discussed using a public/private key cryptography-based authentication mechanism.Lastly,based on geofencing techniques,blockchain-enabled machine-to-machine(M2M)technology is proposed for quarantine management.The step-by-step methodology and test results are proposed to ensure contact tracing and quarantine management.Unlike existing research studies,the security aspect is also considered in the realm of blockchain.The practical implementation of the proposed solution also obtains the results.The results indicate the successful implementation of blockchain-enabled contact tracing and isolation management using IoT and geo-fencing techniques,which could help battle pandemic situations.Researchers can also consider the 5G-enabled narrowband internet of things(NB-IoT)technologies to implement contact tracing solutions.

A systematic literature review of blockchain cyber security

Since the publication of Satoshi Nakamoto's white paper on Bitcoin in 2008,blockchain has(slowly)become one of the most frequently discussed methods for securing data storage and transfer through decentralized,trustless,peer-to-peer systems.This research identifies peer-reviewed literature that seeks to utilize blockchain for cyber security purposes and presents a systematic analysis of the most frequently adopted blockchain security applications.Our findings show that the Internet of Things(IoT)lends itself well to novel blockchain applications,as do networks and machine visualization,public-key cryptography,web applications,certification schemes and the secure storage of Personally Identifiable Information(PII).This timely systematic review also sheds light on future directions of research,education and practices in the blockchain and cyber security space,such as security of blockchain in IoT,security of blockchain for AI data,and sidechain security.

Tracing manufacturing processes using blockchain-based token compositions

Supply chain traceability is one of the most promising use cases to benefit from characteristics of blockchain,such as decentralization,immutability and transparency,not required to build prior trust relationships among entities.A plethora of supply chain traceability solutions based on blockchain has been proposed recently.However,current systems are limited to tracing simple goods that have not been part of the manufacturing process.We recommend a method that allows for the traceability of manufactured goods,including their components.Products are represented using non-fungible digital tokens that are created on a blockchain for each batch of manufactured products.To create a link between a product and the components that are needed to produce it,we propose“token recipes”that define the amount of tokenized goods required for minting a new token.As input tokens are automatically and transparently consumed when creating a product token,the physical process of producing a new item out of existing components is projected onto the ledger.This ultimately leads to the complete traceability of goods,including the origin of inputs.Evaluating the performance of the system,we show that a prototypical implementation for the Ethereum Virtual Machine(EVM)scales linearly with the amount of the input and goods tracked.

A Loosely Coupled Control Architecture Based on Agent and CORBA for Multiple Robots

With the rapid development of information technology, adopting advanced distributed computing technology to construct robot control system is becoming an effective approach gradually. This paper proposes a distributed loosely coupled software architecture based on Agent and CORBA to control multiple robots. This model provides the robot user with agent control units at the semantic level and CORBA provides function interfaces to agent at the syntax level, which shows a good adaptability, flexibility and transparence.

Secure smart contract-based digital twins for the Internet of Things

The proliferation of Internet of Things(IoT)devices that operate unattended providing a multitude of important and often sensitive services highlights the need for seamless interoperability and increased security.We argue that digital twins of IoT devices,with the right design,can enhance the security,reliability,auditability,and interoperability of IoT systems.The salient features of digital twins have made them key elements for the IoT and Industry 4.0.In this paper,we leverage advances in W3C’s Web of Things(WoT)standards and distributed ledger technologies(DLTs)to present a novel design of the smart contract-based digital twins with enhanced security,transparency,interoperability,and reliability.We provide two different variations of that general design using two different blockchains(one public and one private,permissioned blockchain),and we present design trade-offs.Furthermore,we introduce an architecture for accessing and controlling IoT devices securely and reliably,providing full auditability,while at the same time using the proposed digital twins as an indirection mechanism(proxy).The proposed architecture leverages the blockchain to offer notable properties,namely,decentralization,immutability,auditability,non-repudiation,availability,and reliability.Moreover,it introduces mass actuation,easier management of IoT devices,and enhanced security to the IoT gateways,enables new business models,and makes consumer devices(vendor-)agnostic.

Modeling Analysis of Complex Products Resource Integration Behavior Under Distributed Collaborative Technology Innovation Mode

According to new features of distributed technology innovation collaboration of complex products of China’s aviation,in the multi-agent collaborative R&D process,between main manufacturer and suppliers,this paper summarizes the organizational structure and characteristics of collaborative mode of distributed technology innovation of complex products,basing on the technological innovation and resource integration of complex products,and treating resource contribution rate as a key parameter. It establishes multi-agent resource integration collaborative symbiosis model under distributed collaborative technology innovation mode based on symbiosis theory. And finds that some factors such as the basic attributes of the enterprise,the mutual influence of resources among enterprises and the behavior decision of the main manufacturer have some effects on the resource integration using stability analysis and simulation analysis,which provides a theoretical basis for the main manufacturer to optimize the behavior of suppliers’ resource integration.

A review of previous studies on the applications of fiber optic sensing technologies in geotechnical monitoring

Geotechnical engineering is characterized by many uncertainties,including soil material properties,environmental effects,and engineering design and construction,which bring a significant challenge to geotechnical monitoring.However,conventional sensors with several inherent limitations,such as electromagnetic interference,signal loss in long-distance transmission,and low durability in harsh environments cannot fully meet current monitoring needs.Recently,fiber optic sensing technologies have been successfully applied in geotechnical monitoring due to the significant advantages of anti-electromagnetic interference,stable signal long-distance transmission,high durability,high sensitivity,and lightweight,which can be considered an ideal replacement for conventional sensors.In this paper,the working principle of different fiber optic sensing technologies,the development of fiber optic-based sensors,and the recent application status of these sensing technologies for geotechnical monitoring were comprehensively reviewed and discussed in detail.Finally,the challenges and countermeasures of the sensing technologies in geotechnical monitoring were also presented and discussed.

The cost of privacy on blockchain:A study on sealed-bid auctions

In order to preserve privacy in a blockchain ecosystem,the main objective is to keep a transaction's data private,such as the sender,the receiver,and the amount transferred.The current work studies the cryptographic tools commonly used to achieve this type of privacy,primarily focusing on the Ethereum blockchain.Such tools usually require many computational and storage resources,leading to additional fees.An anonymous auction protocol was developed as a case study to explore these costs,where hiding the identity and the amount of the bids utilizes a variety of cryptographic primitives.The proposed implementation was compared against three sealed-bid auction protocols,which utilize similar cryptographic tools for preserving privacy throughout the auction process.The results show that providing an additional level of anonymity,such as hiding someone's identity,can increase the gas cost significantly,up to 2.5 times,depending on the choice of the cryptographic tools,which determine the usage of the blockchain's storage and computational resources.By adjusting the level of decentralization on the application level by moving some operations off-chain and maintaining the role of the auctioneer,we show that we can maintain anonymity while reducing the gas cost by 40%.

Research on cross-chain and interoperability for blockchain system

At present, there is an urgent need for blockchain interoperability technology to realize interconnection between various blockchains, data communication and value transfer between blockchains, so as to break the ‘value silo’ phenomenon of each blockchain. Firstly, it lists what people understand about the concept of interoperability. Secondly, it gives the key technical issues of cross-chain, including cross-chain mechanism, interoperability, eventual consistency, and universality. Then, the implementation of each cross-chain key technology is analyzed, including Hash-locking, two-way peg, notary schemes, relay chain scheme, cross-chain protocol, and global identity system. Immediately after that, five typical cross-chain systems are introduced and comparative analysis is made. In addition, two examples of cross-chain programmability and their analysis are given. Finally, the current state of cross-chain technology is summarized from two aspects: key technology implementation and cross-chain application enforcement. The cross-chain technology as a whole has formed a centralized fixed mechanism, as well as a trend of modular design, and some of the solutions to mature applications were established in the relevant standards organizations, and the cross-chain technology architecture tends to be unified, which is expected to accelerate the evolution of the open cross-chain network that supports the real needs of the interconnection of all chains.

Trusted data access and authorization protocol

Threshold proxy re-encryption(PRE) authorizes the data access right of data subject to multiple proxies, who authorize the right again to delegatee to accomplish the end-to-end data encryption process from storage to authorization. Based on threshold PRE algorithm, in order to build a complete trusted data storage and authorization system, the four protocols, which are data access protocol, authorization proxy protocol, authorization proxy cancellation protocol and data reading authorization protocol, are defined completely. On that basis, an efficient data searching method is constructed by specifying the data delegatee. At last, to ensure the right to know of data, the audit log is processed with trusted data right confirmation based on distributed ledger technology. Meanwhile, a parallel data right confirmation processing method is defined based on hierarchical derivation algorithm of public and private key. In the end, the performance evaluation analysis of the protocol are given. Trusted data access and authorization protocol is convenient to build a complete data processing system on the premise of protecting data privacy based on public cloud storage system or distributed storage system.

Recovery of rare and precious metals from urban mines —— A review

Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional （pyrometallurgical, hydrometallurgical, and biometallurgical processing）, and emerging （electrochemical, supereritieal fluid, mechanochemical, and ionic liquids processing） technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used tbr RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies electrochemical, supercritical fluid, ionic liquid, and mechanochemical have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.

Verification and Validation for data marketplaces via a blockchain and smart contracts

Actual challenges with data in physical infrastructure include:1)the adversity of its velocity based on access and retrieval,thus integration;2)its value as its intrinsic quality;3)its extensive volume with a limited variety in terms of systems;and finally,4)its veracity,as data can be modified to obtain an economical advantage.Physical infrastructure design based on Agile project management and minimum viable products provides benefits against the traditional waterfall method.Agile supports an early return on investment that promotes circular reinvesting while making the product more adaptable to variable social-economical environments.However,Agile also presents inherent issues due to its iterative approach.Furthermore,project information requires an efficient record of the aims,requirements,and governance not only for the investors,owners,or users but also to keep evidence in future health&safety and other statutory compliance.In order to address these issues,this article presents a Validation and Verification(V&V)model for data marketplaces with a hierarchical process;each data V&V stage provides a layer of data abstraction,value-added services,and authenticity based on Artificial Intelligence(AI).In addition,this proposed solution applies Distributed Ledger Technology(DLT)for a decentralised approach where each user keeps and maintains the data within a ledger.The presented model is validated in real data marketplace applications:1)live data for the Newcastle Urban Observatory Smart City Project,where data are collected from sensors embedded within the smart city via APIs;2)static data for University College London(UCL)—Real Estate—PEARL Project,where different project users and stakeholders introduce data into a Project Information Model(PIM).