基于私有区块链的共识算法性能分析

共识算法是区块链框架的核心,解决了分布式网络中节点之间的相互信任问题。然而现有的私有区块链平台缺乏对共识算法性能分析的理论和数据支持。故提出了一种在以太坊和Hyperledger私有区块链平台上评估共识算法性能的方法。通过对延迟和吞吐量的定量分析,获得了具有不同事务数量的共识算法的性能评估结果。结果表明:在平均吞吐量和平均延迟方面,Hyperledger的PBFT算法优于以太坊的PoW算法,两种共识算法的性能差异随事务数量的增加而增加。实验结果可为共识算法的进一步研究提供定量数据支持,为区块链从业者选择共识机制提供指导。     

基于区块链技术的学习成果认证管理系统研究

学习成果认证对构建终身学习体系、建设学习型社会具有重要作用。基于此,文章首先对学习成果认证与区块链技术需求进行了分析,接着构建了基于区块链技术的学习成果认证管理系统。随后,文章介绍了系统各层的功能及其实现,包括逻辑层和数据层中复合型区块链账本、成果档案、优化BFT共识算法等创新设计,以及呈现层和应用层中认证管理、智能合约管理和学习成果的查询分析等模块功能。最后,文章阐述了系统在教学中的应用构想。基于区块链技术的学习成果认证管理系统的构建,为解决开放教育环境中学习成果的认证难题、推进以学生为中心的教学提供了一种新的技术方案。     

基于信任优化的共识算法的区块链知识共享研究实验测试及分析

针对当前区块链的相关共识算法在知识共享中面临网络延迟类型的应对困难,研究为提高区块链的安全性能与网络动态适应能力,在DAG和RapidChain的基础上提出了DAG-Dumbo算法以及ProRapidChain算法,并利用实验对其性能进行验证。实验结果表明,DAG-Dumbo算法的吞吐量比Dumbo算法提高了25%,而DAG-Dumbo算法在带宽达到3000 kbit/s后仍然有所提高。同时,DAG-Dumbo算法时延远低于Dumbo算法,最高不超过2 s。另外,当时间数目为5时,ProRapidChain的平均吞吐量为9×10⁴(tx/s),远远超过RapidChain的平均吞吐量。并且ProRapidChain算法能够对所有的恶意节点进行有效的识别,而每一个委员会的正确节点数量稳定在88%。综合来看,DAG-Dumbo算法有效地提升了区块链中异步共识算法的效率,增强了异步网络环境的支持度。同时ProRapidChain算法也有效提升了区块链的安全性和适应能力。对实际的区块链知识共享具有重要意义。     

一种ABCSAT算法的启发式初始解策略

为了改善初始解在解空间中的分布状况,根据SAT问题的变量极性差异约束,提出一种启发式初始解策略,以解决人工蜂群算法求解策略问题。该方法不仅保留了随机思想,而且设置了变量的取值倾向。实验证明,新策略能够进一步节约求解时间和内存消耗,提高求解成功率。     

基于区块链技术的学分银行系统研究

学分银行是构建终身学习体系和学习型社会的重要途径。基于此,文章首先分析了中心化学分银行存在的管理问题,并对区块链技术进行了解读。随后,文章设计了基于区块链技术的学分银行系统。最后,文章从学分银行联盟链、侧链、主链三个维度,探讨了基于区块链技术的学分银行系统的实现机制。研究基于区块链技术的学分银行系统,对于打破"信息壁垒"、提高学习成果认证和转换的公信力与效率、建设个人的终身学习电子档案有积极的意义,并为学分银行的发展提供理论参考。     

融合区块链技术的社区教育学习成果认证模型及实现机理研究

研究区块链技术对社区教育学习成果进行确权和认证的实现机理,以期提升学习成果数据的流通性和可信度.针对认证过程中存在的效率低、成本高、信息不对称和监管缺失等问题,提出一种融合区块链技术的学习成果认证模型.首先,对模型的基本框架和区块数据结构进行分析;然后,使用权益证明机制(PoS)与实用拜占庭容错算法(PBFT)相结合的混合共识机制实现身份信息和学习成果的认证,并采用多重签名来保障认证过程的安全性和真实性;最后,以"信任值"方式激励多方主体进行交互.将区块链技术的特性应用于社区教育学习成果认证,有助于解决学习成果认证效率低下、学习过程追溯困难、学习成果可信度低和学习者学习动力不足等问题.     

融合区块链技术的社区教育学习成果认证模型及实现机理研究

研究区块链技术对社区教育学习成果进行确权和认证的实现机理,以期提升学习成果数据的流通性和可信度.针对认证过程中存在的效率低、成本高、信息不对称和监管缺失等问题,提出一种融合区块链技术的学习成果认证模型.首先,对模型的基本框架和区块数据结构进行分析;然后,使用权益证明机制(PoS)与实用拜占庭容错算法(PBFT)相结合的混合共识机制实现身份信息和学习成果的认证,并采用多重签名来保障认证过程的安全性和真实性;最后,以"信任值"方式激励多方主体进行交互.将区块链技术的特性应用于社区教育学习成果认证,有助于解决学习成果认证效率低下、学习过程追溯困难、学习成果可信度低和学习者学习动力不足等问题.     

布尔可满足性问题研究综述

布尔可满足性（简称SAT）问题是研究最广泛的NP-完全（简称NPC）问题之一。编码、预处理和求解算法是SAT问题求解的3个关键技术,近年来涌现了大量成果。SAT问题广泛应用在生产和生活中, SAT求解技术的健壮性和综合性能迫切需要进一步提升。从SAT问题分类、SAT问题应用领域、研究现状及面临的挑战等方面对相关研究成果进行梳理。     

基于区块链技术的学生综合素质评价系统设计

学生综合素质评价是推动新时代育人方式和评价系统综合改革的关键。我国经过10余年的学生综合素质评价探索,基础教育的育人方式和高校招生考试改革均有较大转变,但也存在综合素质评价效用不高、权责不清、客观公正不足、安全可靠性不敷等问题。区块链作为一种新型的分布式数据存储技术,具有去中心化、点对点传输、共识机制、加密防伪和智能合约等技术优势。构建和应用基于区块链的学生综合素质评价系统,不失为解决学生综合素质评价问题的一条有效途径。基于Hyperledger Fabri设计的学生综合素质评价系统架构包括基础设施层、网络层、共识层、数据层、智能合约层、接口层和应用层,可在宏观治理层面支持弱中心化的评价联盟运行,在中观评价层面实现安全、可信、溯源的数据录入,评价实施,结果查询与应用等评价过程。但建设和应用基于区块链的学生综合素质评价系统是一项系统性工程,需要不断明确和解决理念、技术、数据、算法、制度等方面的问题。     

高校科研诚信存在问题的改进探讨——基于区块链技术的视角北大核心

区块链具有分布式存储、非对称加密、共识机制和智能合约四大核心技术,通过自信任的弱中心化底层架构技术,构建一个公开透明的账本系统,使所有节点都能进行安全的数据交换,从而运用技术手段解决信任问题,为知识产权的确权提供了一种有效途径。文章从建立科研诚信体系的时代背景入手,探讨了区块链技术解决科研诚信问题的机理和基本思路,设计了由数据层、网络层、共识层、激励层、合约层和应用层构建的区块链高校科研诚信体系架构,设计了由用户管理、成果上链、成果创新查验、监控预警、失信惩戒五个模块组成的区块链高校科研诚信系统,为遏制学术不端、构建诚信科研环境提供了较好的借鉴和参考。     

基于用户画像的区块链激励设计

区块链由于具有不可篡改、数据可追溯的性质,已应用于金融、版权、数据交易等多个领域。在公交车司机行为画像基础上,设计一种基于用户画像的区块链激励设计方案。首先定义司机画像评分方式,将评分作为区块链产生的依据,然后根据司机画像设计智能合约机制,最后提出区块链激励构架与功能组件。该方法有利于解决考核过程中的去中心化问题,为公司提供一种新的激励制度设计思路。     

基于区块链的高校联盟学分管理系统研究

促进高校联盟主体间信任是区块链在高等教育领域应用热点。以EduCTX项目为例,阐述基于区块链的跨校学分管理系统业务模型、技术模型,总结优缺点与面临的挑战。EduCTX项目以学分登记、跨校转移、证伪为核心业务,以高校、学生、雇主为服务对象,构建以ARK技术、Dpos共识机制、Github开源平台为基础的六层开放联盟式学分管理区块链系统。区块链去中心化特征与高校松散联盟需求相契合,分布式账本增强教育合作的信任感,降低成本。但也存在学分可交易性差,使之很难形成有效激励机制,对高校与学生不可信任的预设有悖于学校立德树人使命,学分记录永久不变不利于实现终身学习等问题。     

信息技术背景下基于问题解决教学模式的学习环境设计

信息技术的发展为学习者提供了最为丰富的学习资源和多样的学习情境.基于问题解决教学模式中的学习环境设计是把问题作为学习目标,强调问题情境创设的真实性,在此基础上创建基于问题解决教学模式的学习环境设计模型,通过计算机网络技术和数据库技术使该模型得以实现.     

Children’s solving of ‘Tower of Hanoi’ tasks: dynamic testing with the help of a robot

Abstract

The present study investigated the usefulness of a pre-programmed, teleoperated, socially assistive peer robot in dynamic testing of complex problem solving utilising the Tower of Hanoi. The robot, in a ‘Wizard of Oz’ setting, provided instructions and prompts during dynamic testing to children when they had to solve 3?D Tower of Hanoi puzzles. Participants were 37?second grade 8-year-old children, of whom half received graduated prompts training between pre-test and post-test, delivered by the robot, and half did not. It was found that children’s progression in task accuracy varied considerably, depending on whether or not children were trained in solving Tower puzzles. Trained children showed greater progression in the number of Tower problems that they could solve accurately, made considerably fewer steps, although the Tower puzzles increased quickly in difficulty level. The mean completion time of trained children decreased at a slower rate than that of the untrained children, but both groups of children took considerably more time to think and plan ahead before they started the solving process. Only moderate relations with planning behaviour were found. In general, the study revealed that computerised dynamic testing with a robot as assistant has much potential in unveiling children’s potential for learning and their ways of tackling complex problems. The advantages and challenges of using a robot in educational assessment were discussed.     

Issues in science education: problem‐solving,creativity and originality

In this paper the author explores the concept of problem‐solving as generally employed in the science education literature and suggests that a useful distinction can be drawn between puzzles, for which solutions are known or assumed to exist, and problems, for which no solution may be possible. The ability to recognize a problem, it is suggested, is possibly more important than its solution and this is dependent upon the experience, knowledge and interests of the individual. Successful encountering of problems and puzzles and the relationship of this activity to originality and creativity is also discussed. It is proposed that both puzzle and problem‐solving activities are important to provide in school science but that too little attention is paid to real problem‐solving with the result that the specific skills required are not practised.     

"三方互动3+3"技师培养机制的创建

为了逐步解决经济发展方式转变和产业优化升级对高素质、高技能型人才迫切需求的问题,高职院校应以校企合作为平台,创建人才共育、过程共管的三方互动3+3技师培养机制.这一培养机制可以解决高职学生职业发展能力和高技能型人才紧缺等问题,从而形成互为依托、资源共享、分段实施、共创双赢的高职院校办学特色.     

Children's Reasoning as Collective Social Action through Problem Solving in Grade 2/3 Science Classrooms

Research on young children's reasoning show the complex relationships of knowledge, theories, and evidence in their decision-making and problem solving. Most of the research on children's reasoning skills has been done in individualized and formal research settings, not collective classroom environments where children often engage in learning and reasoning together to solve classroom problems. This study posits children's reasoning as a collective social activity that can occur in science classrooms. The study examined how children process their reasoning within the context of Grade 2/3 science classrooms and how the process of collectivity emerges from classroom interactions and dialogue between children as they attempt to solve their classroom problems. The study findings suggest that children's reasoning involves active evaluation of theories and evidence through collective problem solving, with consensus being developed through dialogical reasoning.     

A Problem‐based Learning Model for Teaching the Instructional Design Business Acquisition Process

There is a growing emphasis on utilizing a problem‐based learning [PBL] pedagogy to help instructional design students gain an understanding of the complex forces operating within an actual design environment. However, little literature exists to suggest that PBL is being used to teach the process by which instructional design firms and practitioners secure work—the Instructional Design Business Acquisition Process (IDBAP). This study outlines a conceptual framework for using an adapted problem‐based learning model for teaching the IDBAP, which consists of writing a response to a request for proposal (RFP), developing a working prototype, and orally presenting the solution. This study also examines the impact of a PBL pedagogy on students' perception of their confidence in solving instructional design problems. The results of this empirical research indicate that students who participate in a problem‐based learning pedagogy gain confidence in their abilities to solve instructional design problems, view themselves in emotional control when solving an instructional design problem, and are more inclined to approach similar problems in the future.