《民间故事》2019年11月（下）刊, ISSN:1005-3948
摘要:当前的云教学网络学习平台中，存在教学管理难度大、考核方式灵活性差，各种教学活动行为的评分难以衡量等问题，为此，本文提出一种基于区块链技术的云教学终端系统平台解决问题。系统以“一课程一节点，脑力即算力，Token为辅”的设计思想以及与区块链特性相结合的机制，来适应云平台各种教学环境等情况；系统以以太坊联盟链POA(Proof-of-authotity)共识为基础搭建云教学平台框架，采用本地数据库结合区块链分布式存储教学信息，智能合约实现云平台交互功能。
关键词：云教学终端平台；区块链；设计与实现；智能合约
1. 概述
1. < strong > Overview
区块链技术的终端云教学平台，即从分布式技术存储、智能合约方式降低人为干预教学与学习的过程、降低云教学活动的管理难度角度出发。目前的各种云平台如雨后春笋般出现，但是云教学管理难度和线下教学管理相比，存在灵活性差、考核难度大等问题[1]。
The terminal cloud learning platform for block chain technology, i.e., from the point of view of distributed technology storage, intelligent contracting to reduce artificial interference in teaching and learning processes, and to reduce the difficulty of managing cloud teaching activities. Current cloud platforms appear as rain and rain, but there are problems of poor flexibility and difficulty in testing compared to underline teaching management .
为提高云教学平台学习过程可信任、降低教学活动中人为干预过程[2]，一方面，由区块链替代传统数据库库，采用分布式不可更改的存储方式进行数据的存储，实现学习过程中信息数据的可信任；另一方面，采用智能合约的方式，将教学活动、教学管理的实现智能化，降低人为干预的过程，让整个教学环境具有自治性。结合区块链的特性，提出基于区块链的云教学终端平台模型设计。
[2] in order to enhance the credibility of the learning platform learning process by reducing the human intervention process in the learning platform [2] , on the one hand, replacing the traditional database with a block chain to store data in a distributed and unalterable way, and to build trust in information data in the learning process; and, on the other hand, using a smart contract, the intellectualization of teaching activities, the management of teaching, the reduction of the human intervention process and the autonomy of the teaching environment as a whole.
2. 区块链
2.1区块链概念
2.1
区块链技术起源于化名为“中本聪”的学者在2008年发表的奠定性论文《比特币:一种点对点电子现金系统》。区块链技术是利用区块链数据结构来验证和存储数据、利用分布式节点共识算法来生成和更新数据，利用密码学的方式来保证数据传输和访问安全、利用由自动化脚本代码组成的智能合约来编程和操作数据的一种全新的分布式基础架构与计算范式。
The block chain technology originates from the ground-breaking paper, Bitcoin: A Point-to-Point Electronic Cash System, published in 2008 by a scholar called “Middle-to-Hear.” The block chain technology is a completely new distributional infrastructure and computational paradigm that uses block chain data structures to validate and store data, use distributed node consensus algorithms to generate and update data, use cryptography to secure data transmission and access, and use smart contracts made up of automated script codes for programming and operating data.
2.2区块链概念
区块链是由区块有序串联而成的链式数据结构[3]，由区块头、版本号、前区块Hash、Merkle树根、时间戳等组成。区块头是当前区块的Hash值；时间戳记录当前区块的产生的时间；Merkle树根作为区块的存储器，其每一个叶子节点存储当前区块存储的内容，每一个叶子节点都是逐渐向上传递至父节点直到Merkle树根，由此判定被篡改的节点位置。
The block chain is a chained data structure made up of blocks in an orderly chain of blocks , consisting of block heads, version numbers, front block Hash, Merkle root, time stamp, etc. The block head is the current block's Hash value; the time of the current block's creation is time stamped; the Merkle root is the memory of the block, with each leaf node storing the contents of the current block, and each leaf node is gradually passed up to the father's node and up to the Merkle root, thereby determining the location of the altered node.
图1：区块链结构图
Figure 1: Structure of the block chain
2.3以太坊联盟链与POA共识机制为基础实现方式
2.3 > is achieved on the basis of the Taiya Alliance chain and the PAA Consensus mechanism
区块链以开放程度分类，可分为公有链、私有链、联盟链。公有链即公开，所有区块链节点信息公开；私有链即私有，区块链节点信息只对内部开放；联盟链介于公有链与私有链之前，区块链节点信息对联盟成员开放。通过联盟链方式搭建云教学终端平台一是可以保证教学数据仅在联盟成员中相互流通，即具有保密性，也在未来提供可扩展性[4]。
Block chains are classified by degree of openness and can be divided into public, private, and union chains. Public chains are open, with information on all block chains open; private chains are private, with information on block chains only open to internal; union chains are open to coalition members before public and private chains. The building of cloud-based learning terminal platforms through a coalition chain is a guarantee that teaching data will circulate only among members of the alliance, i.e. confidentially, and will also provide expansionability in the future.
区块链共识机制主要分为几类：POW（Proof-of-work）即工作量证明机制、POS(Proof-of-stake)即权益证明机制、Dpos(Delegated-proof-of-stake)即委托权益证明机制、POA(Proof-of- authotity)即权威证明机制。这几类共识机制根据不同的应用场景被使用各类应用中。通过对以上几类机制的分析，云教学终端管理系统采用了以太坊的POA共识机制，通过选举出信任节点进行打包交易以及完成出块任务。
The block chain consensus mechanism is divided into several categories: the Proof-of-work, the Workload Certification Mechanism, the Proof-of-stake, the Pro-Protection Mechanism, the Delegated-proof-of-stake, the Commission Certification Mechanism, and the Proof-of-Authority, the Authority Certification Mechanism. These types of consensus mechanisms are used in various applications based on different applications.
2.4 POA机制的联盟链特点
2.4 POA the coalition chain characteristics of the mechanism
以POA为基础的联盟链具有若中心化、信息不可篡改、可信任、数据可追溯、数据分布式存储等特点，与云教学平台相互结合，即可以保证课堂教学、学习过程可信任，实现降低教学管理过程人为干预。
The POA-based coalition chain is integrated with cloud-based learning platforms if it is centralized, information is inexorable, trusted, data retrospective and data-distributed, so as to ensure confidence in classroom teaching and learning processes and to reduce artificial interference in teaching management processes.
(1)若中心化。基于区块链的分布式特性，教学、学习过程中的数据会形成区块链账簿形式存储在节点中[5]；其次，通过POA共识机制，由节点对整个课堂产生的数据进行交易打包上传至整个区块链网络，保证了以课堂为中心产生的数据自动化存储至区块链网络中，减少人为干预数据过程。
(2)信息不可篡改。在整个教学活动中，如：教师批改作业完成情况、学生是否接收通知、学生作业完成情况、是否观看完视频、学生考试成绩等，这些行为所产生对应的网络数据都将以对应的Hash方式存储至区块链中，一旦被存储将无法被篡改[6]。
(2) information cannot be tampered with . The corresponding network data generated by these acts will be stored in the corresponding Hash chain and, once stored, will not be tampered with [6]
(3)可信任。基于POA共识机制搭建的联盟链，如果其中一个信任节点要对整个区块链进行操作，需要整个信任节点的三分之二允许情况下，才能进行操作。一旦发现数据被篡改可以追溯至数据的发起方，身份的确认保证整个区块链网络的可信任。
(3) can trust . A coalition chain based on the PAA Consensus mechanism can operate only if two-thirds of the entire trust node is allowed to operate if one of the confidence nodes is to operate. Once it is discovered that the data has been tampered with and can be traced back to the originator of the data, identification guarantees trustability in the entire network of block nodes.
图2:POA共识机制架构图
Figure 2: Structure of the PAA Consensus Mechanism
3. 基于区块链云教学终端平台设计模型
3.1 系统采用一课程一节点，脑力即算力，以Token为辅的设计思想，让整个教学、学习过程可追溯、可信任，提供动态自主性教学管理。
3.1 applies a section of the course, brain is arithmetic, accompanied by Token design ideas, allowing the whole teaching, learning process to be retrospective and trusted, and providing dynamic and autonomous teaching management .
(1)课程节点
(1) node of the course
如果将所有云教学课程数据都放在整个区块链中，后面随着更多的课程、学生、教师等各类数据不断增多，存储难度将变得非常困难，整个数据难以进行管理。所有这里提出以每个课程为节点，即该课程下所有教学活动产生的数据遵循“统一前缀值+身份标示+Hash”的命名规则，并且借助本地存储系统将数据进行分课程整理存储。降低了区块链对于分散、臃肿数据存储的难度和管理难度，更好的实现即信任可追溯的数据存储功能[7]。
If all cloud curriculum data are placed in the entire block chain, the difficulty of storing them will become very difficult as more and more types of data, such as curricula, students, teachers, etc., become more available, and the entire data will be difficult to manage. All of the proposed nodes for each course, i.e., the data generated by all teaching activities under the curriculum follow the naming rule of “harmonized prefix + identification + Hash” and the data are stored separately through local storage systems. The difficulty of the block chain with respect to the storage of dispersed, swollen data and management is reduced by the difficulty of [7]/a>.
(2)脑力即算力
在整个云教学的教学环境下，无论是教学还是学习的行为都难以考核，没有一个实际的指标去考核某种行为是否完成。比如，学生观看网络视频，作为教师没有办法时刻知道每一位学生是否观看了视频，从而难以对学生行为进行评分。所以提出了脑力即算力的考核方式，基于区块链下的云教学平台，系统会将对每个用户进行标示(如年纪+班级+学号+姓名)，当使用者进行观看视频过程中，系统会不定时提出观看过的问题，学生进行作答。这个过程即将学生的脑力转为为算力，并由节点打包此交易信息到整个区块链网络中。其次，学生观看视频、回到问题都是由智能合约自主完成，人为不可干预，并且两个行为数据都将被永远存储。
In the teaching environment of the entire cloud, it is difficult to evaluate behaviour, whether teaching or learning, and there is no real indicator of whether or not a certain behaviour has been completed. For example, students view web videos, and as teachers have no means of knowing at all times whether each student has seen the video, making it difficult to rate the behaviour of the student. So a brain-wise or arithmetic approach is proposed, based on the cloud platform under the block chain, the system will mark each user (e.g., age + class + + name) and, when the user is watching the video, the system will ask questions that have been watched, and the student will answer them. This process will transform the student's brain into arithmetic and package the transaction information into the entire network of blocks.
(3) Token为辅
(3) Token is supported by
云教学环境下，教学活动的过程中的行为难以直接用学分进行兑换，由此提出token为辅的机制，将教学活动中的行为与token进行挂钩。在该平台下，使用者所有的行为或者操作都将以token的形式被表述。以观看视频为例，使用者在打开视频并观看完成的视频，系统会自动给予token奖励；使用者在完成视频过程中答题，也会给予token的奖励。通过token为辅的机制，贯彻整个区块链云教学活动，最后是将token和学分进行挂钩，按一定比例得出某某学生在本学期该课程中所获得的学分。其次，token可以被看作奖励，通过token提供免费兑换一定奖品，具有激励学生的性质。Token为辅的机制即激发学生更多的学习兴趣，也可看作考核学生教学活动的标示。
In a cloud-based environment, behaviour in the course of teaching activities is difficult to convert directly to credits. Token-backed mechanisms are proposed to link the behaviour of teaching activities with token. Under this platform, all actions or actions of users are expressed in the form of token. For example, token is automatically awarded to users who open videos and watch completed videos. The system gives totoken an incentive to answer questions in the course of completing the video. Token, as an aided mechanism, implements a whole series of token teaching activities, and, finally, token-token and credits are linked in proportion to a given student's score in the course. Second, Token can be seen as an incentive to exchange certain prizes free of charge through token, which has the character of stimulating students.
3.2系统架构
3.2 system architecture
基于区块链的生姜产品柔性可信溯源系统架构，主要由数据采集层、存储层、应用层、交互层构成。
A credible traceability system architecture for ginger products based on block chains consists mainly of a data collection layer, storage layer, application layer, and interactive layer.
基于区块链的云教学终端平台系统架构如图3所示，主要由存储层、应用层、交互层、POA网络节点构成。
The structure of the cloud-based learning terminal system, based on block chains, consists mainly of storage layers, application layers, interactive layers and POA network nodes, as shown in figure 3.
(1)存储层
(1) storage layer
存储层由区块链的分布式存储和本地集中式存储共同组成，分别存储结构化数据和非结构化数据。基于区块链下的云教学各个教学活动的参与者，有着自己特定的身份表示，根据区块链上的存储Hash定位到本地数据的Hash，从而确保数据的不可伪造性，保证数据 存储安全；通过与本地数据库相结合，更加方便进行对数据的规范管理与灵活使用。
The storage layer consists of distributed and centralized local storage of block chains, where structured and unstructured data are stored separately. The participants in each teaching activity based on cloud under the block chain have their own specific identification, location of the Hash on the block chain to local data, thus ensuring that the data is not forged and that the data are stored securely; and the regulatory management and flexible use of the data is made easier through integration with local databases.
(2)应用层
应用层为云平台使用者提供服务。在整个教学活动、教学管理过程中，使用者通过各个智能合约接口，不断将参与者的教学、学习、管理等行为过程产生的数据以调用智能合约接口的形式上传数据至区块链网络以及本地数据库。
The application layer provides services to cloud platform users. Throughout the course of teaching activities, teaching management, users continuously upload data from the participants’ teaching, learning, management and other behavioral processes through various smart contract interfaces to the block chain network and local databases in the form of calls to the smart contract interface.
(3)交互层
交互层主要包括对Web应用、微信小程序、微信公众号等，是提供系统与不同使用平台的接口，更加方便的使用系统功能。
The interface consists mainly of Web applications, micro-message, micro-message, etc., to provide interfaces between the system and the different use platforms and to make it more user-friendly.
(4) POA网络节点
(4) POA network node
POA网络节点是本系统的核心，由多个信任节点组成的共识机制委员组，主要是对通过智能合约产生的交易信息进行打包，将交易信息内的数据存储至区块链网络中，并广播给所有POA网络其他节点完成整个网络数据的一致性。
The POA network nodes are at the heart of the system, with a consensus mechanism membership consisting of multiple trust nodes, mainly packaged transactional information generated through smart contracts, stored data in the transaction information in a block chain network and broadcasted to all other POA network nodes to complete the entire network data consistency.
图3:POA共识网络组
Figure 3: POA Consensus Network Group
3.3 模型应用过程遇到的问题以及解决措施
3.3.1 token生产
3.3.1 tokenfor production
区块链云教学中token的生成，token的生成通过以太坊代码的形式进行生成，生成代码如下：
Token generation in block chain cloud teaching, token generation in the form of Taiwan code, with the following code:
图4:token生成代码
Figure 4: Token Generation Code
3.3.2存储内容以及数据格式
3.3.2
基于区块链的云教学区块链系统存储键值对数据，通过以课程为节点对象，本系统已课程代码、班级ID、学号、姓名等信息组成为键，以课程教学活动行为等产生的交互数据信息为值，通过JSON格式样式对键、值信息作为云教学数据存储形式，样式如下：
Key pairs of data are stored in the cloud education block chain system, which is based on block chains. By using courses as nodes, the system has been made up of course codes, class IDs, school numbers, names, etc., using interactive data messages from course teaching activities, etc., as a form of cloud education data storage using JSON formatting styles, value information, as follows:
4. 总结与展望
4. > summing up
本文通过研究对比目前的云教学平台模型不足的基础上，通过结合区块链POA(Proof-of-authotity)共识机制为基础的架构上和运用以太坊智能合约的便利等特点，设计了基于区块链的云教学终端平台模型。并通过结束以平台使用者观看视频为例给予讲解本系统中部分功能的使用。系统具备存储数据的安全可靠性、数据不可更改性、数据来源可追溯性，将整个云教学活动过程抽象化出来，以脑力即算力的模式将整个区块链云教学平台运作起来。其次，通过智能合约的接口，将教学管理等工作减少了人为干预，所产生的数据更具有说服力以及可信任。并且以token机制为辅，贯穿整个区块链云教学平台，具有一定学习激励效果，提高学生在线学习的动力。
On the basis of a study comparing the inadequacy of the current cloud pedagogic platform model, the design of the cloud pedagogy platform model is based on a combination of architecture based on the POA (Proof-of-authity) consensus mechanism and the ease with which the pedagogic contracts are used. The use of some of the functions in the system is made possible by the end of the example of viewing video by the platform users. The system has a secure reliability of stored data, data integrity, data traceability, abstraction of the entire cloud pedagogic process, operating the entire pedagogic pedagogic platform in a brain-based or arithmetic mode.
本文旨在为当代云教学环境下提供更加合理可靠的新的设计思路以及解决方案。整个区块链云教学系统还有进一步待完善的空间，有以下几个方面：以联盟链的形式开展区块链云教学平台，可以提供未来更多的教学机构加入，实现数据流通、资源互享，但目前开发难度较大需要进一步研究测试；其次，结合区块链的分布式数据存储方式对数据进行存储管理，还需要研究更加高效的数据存储和保障方案；最后，希望推动区块链技术的快速发展，实现区块链技术在教育领域的广泛应用与实践。
The aim of this paper is to provide a more rational and reliable new design and solutions for the contemporary cloud teaching environment. There is still room for further refinement of the whole block chain learning system.
参考文献：
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