Kun Niu＊, Haizhen Jiao, Peng Xu, Jian Kuang, Xiaoyan Zhang

Abstract: Traditional practical teaching has problems on low reusability, high cost and low collaboration ability. To solve these problems, this paper proposes a solution that is to build and use a novel practical teaching platform based on cloud computing. By utilizing advanced information technology, for example, cloud computing, this solution can present a unified service system providing practical teaching resource management, innovation resource management and knowledge management both inside and outside class. Moreover, an instance implementing the cloud-based practical teaching unified services system, Yun Hai, would be detailedly discussed in this paper. The system deployment, resource configuration and matched practice teaching mode will be presented. Yun Hai is independently developed by State Key Laboratory of Networking and Switching Technology and has been deployed and employed in many institutions. To verify the effectiveness of this teaching platform, we take Data Mining, a representative course of computer science, as an example, and analyze how the system would perform when applied to such course which contains cross-disciplinary knowledges. The practice indicates that this teaching system and practical teaching mode can improve convenience and flexibility on practical teaching resource.This kind of one-stop service can contribute to the overall teaching quality improvement.

Key words: cloud computing; practical teaching; one-stop; modern education Informatization

1 Introduction

Software engineering courses are extremely important in computer science courses, which stress the importance of theoretical, comprehensive, and practical properties[1]. In particular, the enhancement of professional knowledge is implemented from practice of high intensity, real, concrete and complete software project development, from which one can get software development experience[2]. However, traditional teaching reform still has plight[3]and traditional practical teaching has limitations such as low reusability, complicated configuration, high cost, low collaboration, and so on.Taking data mining course as collaboration, and so on. Taking data mining course as an example, existing traditional experimental environment cannot meet the demand of experiments, and it is urgent to build a practical environment to support new technique course.How to break the separation between traditional theory and practical teaching, to achieve the full linkage among the software courses and establish foundation of fitting courses to MOOC (Massive Open Online Courses)model and flipped classroom teaching model, gradually becomes the concern of education informatization.

In view of the above problems, we put forward the corresponding solution——a one-stop practice teaching comprehensive service system based on cloud computing and a cloud platform we developed independently. Cloud computing has received extensive attention all over the world as an advancement in the field of information technology because it fundamentally changed the traditional IT infrastructure, application deployment and usage patterns. The features of cloud computing such as flexible resources, versatility, low cost, high security and reliability, can overcome the shortcomings of the current practical teaching mode and provide technical support and service assurance for building an educational service platform. The application of cloud computing technology to integral teaching of practical and theoretical, and construction of one-stop comprehensive educational practice service system is bound to play a positive role in promoting informatization level in the field of education.

2 Related Work and Research Basis

Prior researches related to education informatization are as follows: paper[4] proposed to combine cloud computing aided teaching with experimental teaching in colleges to reform the teaching of basic computer courses in universities; paper[5] took full advantage of software engineering experiment course, built a “ flipped classroom” teaching model and corresponding cloud computing teaching platform architecture; paper[6]analyzed the advantages and disadvantages of using“cloud” and thin clients to construct computer lab in universities; In addition, many colleges and universities has applied the cloud platform to practice of course;Paper[7] analyzed shortcomings of traditional teaching in C language and explored the use of SPOC to realize flipping classroom and carry out teaching reform under the cloud platform; Paper[8] described the exploration on the reform of computer experimental teaching based on cloud platform; Paper[9] analyzed advantage of using ITbegin platform in J2EE class. With the help of World University City education cloud platform, Zhejiang Industry & Trade Vocational College[10-12]established a new generation of internet space application with cloud computing as the core, effectively solved various problems of education and teaching. Paper[13]introduced an experimental cloud platform, which effectively stimulates students’ interest in the learning process and effectively enhances the earning effect.

2.1 Cloud computing technology

Cloud computing[14]refers to the way of providing computing resources of large-scale data center or supercomputer clusters to users for free or ondemand rental through the Internet. Simply say, cloud computing transfers the calculation, storage and other operations originally on the terminal to supercomputers,as known as the “cloud”, through the Internet. It has several featuresas as following.

Everything is service: In cloud computing model,user can simply use a computer with internet access,to access all resources, including storage capacity,application operating environment, stand-alone applications, which are rented out as “service” by cloud service provider. That is to say, users are no longer heavily dependent on a true IT infrastructure.

Aggregate resources into "pool": A reason why cloud computing is called "cloud" is that all of the resources are aggregated into an abstract huge resources pool.Any physical resource in the pool is abstract and alternative to the overall service, and is scheduled by the resource scheduling module. From the user's point of view, they do not need to concern about which physical device would be provided for their services.

Dynamic adjustment of resources：Another reason why cloud computing is called "cloud" is that the cloud is dynamic. In cloud computing mode, it is able to perform dynamically resource allocation and release as user’s requirement by applying algorithms in a type of plug-in. And when the size of applications or the users of the service increases, it can flexibly extend the services by calling other idle resources in the resource pool to ensure quality of service.

High reliability: Cloud computing platform usually adopts backup measures such as active/standby copy of physical machines or multi-replicas deployment to ensure the high reliability of services. When an instance of a user application hangs down or a physical host in the resource pool fails, the backup copy can be immediately enabled, or a new physical host will be allocated and deployed dynamically, to avoid single point of failure leading to service interruption.

2.2 Cloud computing platform

Cloud computing platform are generally divided into three types according to the type of resources provided[15].IaaS(Infrastructure as a Service):The resources provided by such cloud platform are the utilization of all IT infrastructures, including CPU, memory, storage,network and other basic computing resources. Users can deploy and run any software, including operating systems and application programs. Consumers do not need to manage or control any cloud computing infrastructure but can choose which of operating system, storage space, deployed applications, and part of network components.

PaaS(Platform as a Service): The resources provided by such cloud platform are the application runtime environment and various support capabilities that cooperate the application runtime environment such as deploying user programs to the provider's cloud computing infrastructure. Users do not need to manage or control the underlying cloud infrastructure, but they can control the deployed applications as well as the configuration of the hosting environment running the application.

SaaS(Software as a Service): The resources provided by such cloud platform are capabilities of application software. That is to provide the functionality previously provided by the software installed on the user's local machine.

3 The Present Situation and Pr oblems of Experiment and Practical Teaching of Undergraduate Courses

Cultivating college students' practical ability and innovative spirit is an important goal of improving undergraduate teaching quality. Although the practical education reform in colleges and universities has made some achievements in the reform of practical teaching system, practical teaching materials and laboratories, the reform did not really let practical teaching play a role in cultivating students' ability of performing scientific experiment, strengthening practical ability and enhancing students' professional qualities and social competitiveness because there are still systematic deficiencies both in depth and quality in the curriculum experiment and practical teaching in all institutions at present. Moreover, the lack of necessary communication and interaction between teachers and students is also a critical problem. The main reasons come from the following aspects.

3.1 The traditional practical teaching resources have low adaptability and reusability

“Classroom teaching + lab teaching” is an effective way to improve teaching quality of technique courses, however, high requirements for teaching(environmental) resources of the traditional practical teaching methods using special classroom (laboratory)and low reusability of teaching (environmental)resources lead to higher cost of practical teaching resource allocation. Rapid development of current technologies and continually emerging of new technologies put forward higher requirements for adaptability of teaching resources, which means, the traditional model “configure only once, use many years” will no longer be appropriate. In addition, many colleges and universities universally have the problems of low flexibility and low reusability of practical teaching resources. The situation that many universities has more than one campus brings challenges for the repeated construction of practical teaching environment.The existing traditional experimental environment can not meet the experimental requirements of some courses. Therefore, it is urgent to build a practical environment supporting new technique courses to support the development of the teaching.

3.2 The traditional practical teaching courses have low cooperation ability with each other and can not form joint force

At present, although it has been fully considered and proved that there are succeeded and supporting relationships among contents of courses during the compilation of syllabus, the effect of teaching is still limited by the old-fashioned ways of organizing teaching content and providing teaching resources.Courses are often separated from each other, teaching materials inside and outside class and practice materials are independently developed, unable to form synergy,so there is an urgent need for one-stop practical teaching unified services system to effectively break the barrier between courses (especially between the theory and practice of courses).

3.3 Complicated traditional practice teaching conf guration affects the effciency of innovation

“Innovative practice” is an important source for academic researches and application researches in universities, an effective complement to classroom teaching and a further extension of practical teaching.Though the vibrant student team can often get dazzling sparks under the guidance of experienced “innovative mentors”, the value of innovation should not be merely reflected in ideas, but also researches and implementations carried to realize the idea. However,the innovation team of college students often suffer from the duplication of labor and the cost of complex back-end system configuration and maintenance, and it is critical to reduce resource allocation and maintenance costs for innovative practices by a unified back-end service provider that has the property of open, onestop, “no worries about the rear”, flexible and easyto-use. This kind of development environment could be powered by multiple operating systems and crossplatform software.

4 Implementation of the Practical Teaching Unified Service System and Teaching Model Based on Cloud

4.1 “Yun Hai” platform

“Yun Hai”, a cloud computing platform with completely independent intellectual property, has been developed independently by State Key Laboratory of networking and Switching of Beijing University of Posts and Telecommunications. It can provide mature IaaS/PaaS/SaaS service and currently has been deployed in multiple agencies (e.g. China Telecom.,Huabei Oilfield, Huawei Technologies, The 54th Research Institute of China Electronics Technology Group Corporation).

Platform’s architecture of software configuration is“SaaS over PaaS, PaaS over IaaS”, which means only IaaS platform is deployed on the basis of the system hardware, PaaS platform and the services on which PaaS relies are built on IaaS platform in the way of virtual machine, and SaaS applications are deployed on top of PaaS, as shown in Fig. 1.

Fig. 1 System software deployment.

IaaS subsystem: IaaS subsystem provides users with three main functions. First, applying for a cloud host. Users can apply for a cloud host according to their need. They are able to choose operating system template and customize the hardware. Second, applying for a cloud drive, users can apply for different capacity of the cloud hard disk according to their needs. Third,managing cloud hosting. Users can check each virtual machine under their accounts and complete the various operations on the virtual machine. In addition, system allows administrators to complete the management of hardware resources, virtual resources, users, account of platform in a unified interface. IaaS subsystem will provide necessary IT Infrastructure for teaching and innovation practice with high efficient utilization of hardware resources through the unified purchase and construction of a hardware resources.

PaaS subsystem: PaaS subsystem provides users with four main functions. First, Java Web application hosting. Users of cloud platform can host application by applying for an account of cloud platform and uploading the application package (War package)developed locally without buying or configuring server.Second, host application hosting. Users can publish any port of any cloud host under their account as an application. Third, application test. Users can perform the test of their applications hosted by applying for a temporary test domain name. Finally, application flow distribution. Users can publish multiple versions for one application and configure the application request ratios supported by each version through the management interface. PaaS subsystem can further simplify the workload and technical complexity when students configure and use the application runtime environment in innovative activities so that students can focus more on innovation.

Group-Oriented knowledge management SaaS Applications：SaaS system supports multiple service applications. Through cloud platform, users can publish multi-media information, create lists of knowledge to organize discrete knowledge blocks, accurately locate knowledge points by retrieving knowledge categories quickly, comment on each other interactively through e-mail and online message to accelerate knowledge sharing. In addition, users can also form and manage learning groups where users can share knowledge,and users can gain different kinds of knowledge by joining different groups because knowledge is not shared across different groups. The system supports the creation and management of enterprise accounts and provides knowledge management services for specific user groups with stronger management capabilities and better resource independence. The use of grouporiented knowledge management SaaS applications,through online knowledge management applications,can achieve efficient sharing and smooth collaboration of knowledge both inside and outside the curriculum. It can also achieve the controlled diffusion of knowledge while ensuring the effective circulation of knowledge.

4.2 Research and practice of cloud - based practice teaching system and teaching model

4.2.1 Practical teaching unified services system construction

Practical teaching unified services system provides one-stop services including practice teaching material provision and management, innovative practice resource provision and management, and inside and outside curriculum knowledge sharing by managing students using advanced computing technologies such as cloud computing. Practical teaching unified services system includes two parts: practice teaching unified services platform and teaching mode based on it. The platform concentrates to solve the two major problems which are faced in experiment and practice teaching in undergraduate course: First, the existing traditional experimental environment cannot meet the experimental needs of some courses; Second, there is urgent need to build a practice supporting environment for new technology course. Schematic diagram of deployment of the platform is as shown in Fig. 2.

Through the restructuring of existing cloud platform“Yun Hai”, the platform has provided strong technical support for the following three aspects in teaching reform.

Fig. 2 Schematic diagram of deployment of the practical teaching unif ed services platform.

(1) Provide practical teaching resources to expand“Classroom teaching”: Learn from the MOOC model and flipped classroom model, to provide students with all kinds of online resources required for teaching,including various types of operating systems, various types of software development environments, various large and medium-sized applications required for teaching and training students.

(2) Provide innovative and practical resources to help “innovate”: Providing students with cloud server resources, cloud application hosting environment in order to unify operation and management of cloud resources can let students involved in innovative practice and focus more “innovation” instead of cumbersome maintenance of IT resources, reduce the cost of innovation and improve the efficiency of innovation.

(3) Achieve students’ knowledge inside and outside class well gathered, shared and managed: Gathering essential knowledge points and reference materials from teachers in each course and research results,feelings and experience of students in each course together as multi-media resources, and offering students with one-stop knowledge sharing, management and search services. These services can break the “gap”between different courses or between knowledge acquired from class and extracurricular and form a joint force of knowledge gathering and let aggregated knowledge create greater value.

At present, the platform has been put into use in the practical teaching of School of Software Engineering of Beijing University of Posts and Telecommunications,serving more than 300 students.

4.2.2 Teaching model based on practice teaching unif ed services platform

Changes brought by the unified practical teaching services system mainly result in the movement from closed spoon-feeding teaching mode to the opening of teaching process, and the integration of theory and experiment teaching. Effects are mainly from three aspects: First, the practice teaching processes dispersed in various courses is integrated into a comprehensive and integrated practice system to form a disciplinary knowledge system, which has good effects on software engineering. Besides, unified platform for teachers and students in different campuses to use can greatly improve resource utilization, and can upgrade and expand functions of the platform according to the teaching and practical needs or perform targeted improvement at any time to support practical teaching conveniently and effectively. Consequently, the practical and theoretical can supplement each other.Secondly, classroom teaching and practical teaching are closely integrated. For teachers, they can either deliver exercises when teaching theory in classroom or quote content of classroom teaching in practice process. By doing this, the coherence between classroom teaching and practice teaching will be substantially improved.For students, there is no need to go to a specific lab to practice, they can access and use multiple practice teaching resources just with their personal computer.Thirdly, knowledge can be efficiently aggregated,managed and proliferated. Knowledge sharing platform gathers knowledges of in-class learning and extracurricular learning of each student, and teachers and students can share, manage and retrieve knowledge with the platform, to form a joint force of knowledge gathering.

With the help of practical teaching unified services system, teachers can focus on designing content of classroom teaching, after-school study and practice exercises based on relationships between courses. As shown in Fig. 3 and Fig. 4, the platform is responsible for organizing knowledge and teaching resources, as well as management and maintenance of practice environment template which can be fixed and expanded at any time crossing courses and terms with different needs of courses. Furthermore, teachers can connect theory with the actual practice in classroom teaching to form concordance between all of the individual parts of the course.

Students can select courses and join the corresponding group through the platform and look up courseware, experiment requirements,knowledge structure, and knowledge vein between courses. When teachers demonstrating in class, students can get a cloud host with corresponding environment on a click, without building environment on PC to practice in class together with teachers. Furthermore, students can interact through instant messages in the group,and teachers can answer in time. After school,students can review the content of classroom teaching and do more practices on the platform.With the platform, students can also manage personal knowledge, express their opinion, search for knowledge quickly and join the interesting groups to communicate and conduct innovative practices.

Practical teaching unified services platform can adjust itself by the evaluation from operation data collection / analysis, student comments (quantitative/ qualitative) and feedbacks from teachers to meet the diverse needs of students and teachers.

4.2.3 Practice of teaching model based on practice teaching unified services platform in data mining course

Data mining is a comprehensive, practical course, and an cross-disciplinary subject related with many science fields. It requires student to have a solid computer science knowledge, to master basic knowledge such as “Programming”, “Data Structure” and other subjects. The goal of the course is to guide students to understand the basic principles of data mining and main applications of data mining.

Fig. 3 practice resources for courses from practice teaching unif ed services platform.

Fig. 4 course practice linkage relying on practice teaching unif ed services platform.

Traditional practice teaching mode, which is teachers arrange class tasks, and students complete their practical tasks themselves, ask assistants for help when they encounter problems, has many drawbacks.Firstly, students would encounter many problems in the stage of installing software, and assistants would be overworked because the environments on different computer of students are different; secondly,hosts of universities would be cleared and formatted regularly, which makes students operate repeatedly in class and delay the overall teaching schedule. At last,communications between teachers and students are limited to class teaching time, and students cannot get feedbacks in time after class.

The performance of data mining teaching with new teaching mode based on practical teaching unified services platform are pretty good, mainly in the following aspects.

First, the platform provides each student with a pre-configured cloud host. For teachers, they can just configure the environment of a cloud host and upload data, software and courseware of experiment to the host before class; for students, they can practice or do innovation projects at any time just through applying for a host customized for the practice of data mining course. They can also do pre-class review, after-school review, knowledge development and communicate with each other with services provided by the platform.

Second, teachers and students can instantly communicate with each other online. By communicating with teachers and other students through sending instant message in groups, student can get feedback in time.Meanwhile, messages in groups are convenient for teachers to work on problems and improve efficiency of classroom by avoiding repeatedly work when solving the same problems for different students in different time.

Third, with the platform, teaching process becomes more open, and is unified with theoretical and practical teaching. When teaching in class, teachers can program and debug while teaching theory concept and convert theory into runnable program immediately, which makes students have more detailed, more directly understanding.

Last, by evaluating the practice effect of teaching mode based on practical teaching unified services platform with data mining course, teachers can find problems in teaching process and make targeted solutions in time.

The practice has showed that, classroom teaching efficiency is greatly improved with the novel practical teaching mode based on practice teaching unified services platform. In conventional mode, students should submit their assignments within a week after the class, and very few of the students can complete within the class time and most of the class time would be wasted in solving installation problems. In the mode with cloud, students are able to quickly enter the homework assignments, and most of them can submit assignments in class, and teachers can solve problems of students in class. In addition, students’ feedbacks are good and they are satis fied with the improvement of experimental platform.

5 Conclusion and Expectation

In this paper, the disadvantages of traditional practice teaching are analyzed in detail, and more importantly,the paper puts forward the solution of cloud-based practical teaching unified services system. The system constructs one-stop unified services with advanced computing technologies such as cloud computing,and becomes a complete solution to the problems of the traditional practice teaching. The system can also provide adequate and effective technical support and service support for the practice of modern courses.This article details the platform technology solutions,as well as related issues of platform deployment and resource allocation, which has far-reaching reference significance to explore new teaching mode and the future development of education informatization.

Acknowledgement

This work is supported by the Projects on International Scientific and Technological Cooperation under the National Key R&D Program(NKP)（No.2016YFE0204500）, the National Natural Science Foundation of China under Grants（No.61671081，No.61720106007）, the Beijing Natural Science Foundation under Grant（No. 4172042）, the Fundamental Research Funds for the Central Universities, Beijing University of Posts and Telecommunications 2017 Education and Teaching Reform Project （No. 2017JY31）.