Abstract
Multimedia has changed traditional white-blackboard lecture forever and reformed continually the forms and presentation of materials. In this paper, we propose an online marking system. The realization of this system will help improve working efficiency of marking papers, reduce potential cheating and facilitate the teacher storage and analysis students’ examination papers. The system is realized based on B/S structure (Browser/Server structure) which will increase the flexibility of online marking as long as the teacher accesses to the Internet. In the proposed system, some functions in OpenCV have been introduced in procedure such as image segmentation, image enhancement and image rectification to make sure the picture which is shown to the reviewer is correct and clear.In database design of the system, we have fully considered the security issues and the data scalability, we adopt SQL server 2005 as our primary database to ensure comparable large storage capacity and throughout capacity. The system has realized online marking and the storage streamlined, which will improve teacher’s work efficient and provide a reference for learning schedule and a feedback to teaching achievements.
Introduction
Multimedia refers to computer technology and communication technology which is a combination of information handling, transferring and managing. The form of multimedia can be various such as text, image, video, cartoon and so on. Using multimedia technology in school teaching has been for a while, and the application of multimedia technology has forever changed the traditional teaching methods, teaching concept and even teaching criterion. Multimedia has freed teachers from traditional white-blackboard lecturing and students from boring paper books and homework. Nowadays the knowledge in the class is presented in different forms.
The main impact of multimedia on teaching is that multimedia has changed the way of presenting material. Traditionally, teaching requires students present in the class, staring at the book and blackboard, focusing on the teacher and taking notes during the class period. With the development and application of multimedia in teaching, the above teaching processes have changed a lot. The application of multimedia has made the delivery of knowledge and material in different ways such as in text form and visual form that even can satisfy students’ personal taste.
In early applications, multimedia usually is used to present different types of educational materials instead of traditional text-based materials. Multimedia materials can contain words, pictures, sounds and moving pictures which make teaching process more diversified [1]. Teaching using multimedia and visual tool soon increases and some researchers tend to investigate whether different visual environments will enhance the learning experience of students and stuff [2]. It is believed that people tend to be more focused during the learning process when appropriate picture instead of traditional text-based materials [3]. Some researchers claimed that animation is an appropriate teaching material and investigated whether teaching materials combining multimedia animation improve learning achievements. According of survey, they have proposed some cognitive theory [4]. Research on multimedia animation has shown that using multimedia animation during the teaching process can elucidate complex abstract concepts for learners and help learners understand complex concepts [5–7]. Furthermore, multimedia animation also has a positive impact on learner’s motivation, satisfaction, learning achievement and information processing [8–10].
The concepts have been proposed that education should satisfy learners own taste, adapt learning systems and learning materials to students properties, preferences and activities [11, 12]. Rovai proposed that knowledge should construct individually according to the students interaction environment [13]. Jonassen claimed that the students construct knowledge in their own way, there is no predefine learning pathway as students can select learning resources by themselves [14].
Furthermore, some research shows how individual preference for multimedia materials affects learner’s emotion and performance. Some researchers claimed that emotional status and learning are strongly correlated because emotions can effect individual’s attention, meaning creation and formation of memory channels [15, 16]. Some researchers investigated the correlation among different multimedia materials and related emotional states [16, 17] and learning performance [18, 19].
Nowadays, with the help of Internet, multimedia has played a greater role in education, not only just change the teaching mode, but also change and improve all teaching-related process. Students no longer need to present at school but also can communicate with their teachers face to face through remote education system. Some works that focus on real classroom experience capturing have been done which aim to create live lecturing scenarios with real-time two-ways interactions between remote teacher and student sites [20, 21]. The application of multimedia also provides convenience for teachers. With the help of multimedia teaching and telecommuting, teachers can review and feedback to the students’ learning in real time. Checking papers can be implemented as a streamline no matter where the teachers are.
In this paper, we proposed an online marking and storage system, which will streamline the marking process and conduct archival filing. With the help of this system, marking process can be a streamline operation during which teachers are only responsible for the part they are reassigned to which will increase marking efficiency and save their precious time. Besides, backup capabilities of this system will help the teacher grasp learning state of the students and draw up a personalized learning plan for every student.
Key technologies
B/S structure
B/S structure is a change or an improving of C/S structure (Client/Server structure) with the rise of Internet technologies. Compared with C/S structure mode, B/S structure mode has some advantages over the C/S structure mode and has become a popular structure mode in designing applications and systems. The biggest advantage of B/S structure is that you can operate from anywhere without having to install any special software. As long as there is a computer with Internet access which can use the client to zero maintenance. The maintenance and upgrading are simple since the software only need to manage the server line, and all of the client-side only need a browser and do not need any maintenance [22, 23]. Hence in this system, we adopt B/S Server as our basic structure. In C/S mode which divides the software into a two-tier client and server, and the client should have a certain amount of data processing and data storage capacity. In B/S mode, the software application business logic completely in the application server-side implementation while the user behavior response at the Web Server. The differences between B/S and C/S are shown in Table 1. In this paper, the structure of the proposed system is based on B/S structure for its advantages over C/S structure. The structure diagrams of B/S and C/S are shown in Fig. 1.
OpenCV
OpenCV(Open Source Computer Vision) is an open source image processing library, which has provided hundreds of effective image processing functions. OpenCV has provided C++, C, Python and Java interfaces and supports multiple operating systems including Windows, Linux, Mac OS, iOS and Android. OpenCV is independent of external library though external library can be introduced. A lot of real time applications have introduced OpenCV functions in image processing and some practical and creative applications including self-piloting vehicles and new forms of digital art [24–26].
Programming libraries provide common functions or complex capabilities that developers can use in their programs. The OpenCV library provides hundreds of functions that will offer support image generation and processing procedures including capture, analysis, and manipulation of visual information fed to a computer [27–29]. OpenCV provides simple functions like draw a simple shape on the screen with more advanced functions and algorithms for detecting faces, tracking motion, and analyzing shapes. Since the OpenCV is an open source programming library, the programmers can use it with very few restrictions in both commercial and hobbyist projects. In the proposed system, OpenCV functions are introduced in procedure of image segment to divide the image as predefined, enhance the potential dim image and correct skew image [30].
Database technology
Generally a database is a collection of data, while the collection including schemas, tables, queries, reports, views and other objects. The data is typically organized to model which is reflected through aspects of reality in a way that supports to process needed information, such as searching a student name according to its student identity number [31]. A database management system (DBMS) is a computer software application that interacts with the user, other applications, and the database itself and offers the functions of manipulating data. A general-purpose DBMS is designed to allow the definition, creation, querying, update, and administration of databases. Popular database management systems today areMySQL, PostgreSQL, Microsoft SQL Server, Oracle, Sybase and IBM DB2. A database is not generally portable across different DBMSs, but different DBMSs can interoperate by using standards such as SQL and ODBC or JDBC to allow a singleapplication to work with more than one DBMS. Databases are widely used to support internal operations of organizations and to underpin online inter-actions with customers and suppliers. Nowadays, the databases technologies are widely used in Internet, nearly all the operations on the Internet involves database querying and updating.
In this paper, we adopt Microsoft SQL Server, the main interest with this database management sys-tem is that it is suitable for the scalability of distri-buted organization, data warehouse functions for decision support, and is related to many other serv-er softwares integration closely, such as the good performance-to-price ratio, etc. Performance, scalability, and reliability are the main aspects we have considered and the basic requirement for our system.
An overview of the online marking System
With the development of multimedia technology and computer technology, applications of advanced technology in school daily office work have greatly improved office efficiently. In this paper, we proposed an online marking system, there are a few advantages of the system. With the help of this system, teachers can arrange reasonable scheduling, avoid unnecessary actions and no longer need to type students exam result after checking. Since the paper is stored in the server, teachers will easily look over someone’s paper just by entering a serial of number instead of diving in a large number of papers. To insure marking fairness, a subjective question is usually assigned to at least two teachers, if the rating difference is higher than the threshold, it will be the responsibility of the team leader to decide the score, which will reduce the subjective effect and make sure the score of every student fair and just. The system realizes real random distribution of students’ paper, paper reviewer will no access to examinee information which will reduce the possibility of potential cheating. The system has realized real-time score entry and recorded the information of examinee and paper reviewer, by which we can easily count average score and errors.
The marking process of the system is given in Fig. 2.
The system contains hardware and software components. The hardware of the proposed system contains a high-speed image processing computer, high-speed image scanner and campus office network. The structure of our online marking is based on B/S structure mode. The system is deployed in the dedicated servers, the deployment diagram is shown in Fig. 3.
The marking process of the proposed system generally can be divided into three parts, in the following section, detail of the system is given and discussed.
Design of database
With the development of computer technologies, quite a lot of databases have been proposed and mainly can be divided into different types according to their unique characters. Common database systems are relational database, hierarchical database and network database. In this paper, we adopt relational database which is the most popular database. Comparing with hierarchical database and network database, relational database is easy to find and access the files and the data which will be our demand. The database of the proposed database is SQL Server which can provide the capability of vast storage, high-speed data storage and query.In our database, there are mainly three types of data table, namely student table, teacher table and test information table. Teacher table includes teacher identity number, password, name, sex, phone number, address and subject professor. Teacher_Id is the primary key of this table, the teacher information table includes basic information of the teacher. The student table mainly contains student identity number, sex, grade number, class number, candidate number and the type of exam. The Exam information table mainly contains exam identity number, exam name, exam type, test grade identity number, exam state and the length of exam number, identity number of the term and the creator of the exam. Figure 4 shows the relationship among them and the details of the information tables are shown in Tables 2, 3 and 4.
In database design, we mainly follow some principles, Firstly, the function of the system should be perfect and can be continuously optimized and extended. Since the system is an online marking system which should be responsible to students and teachers, the function should be perfect and can accurately present data. Secondly, the use of convenience and maintainability. The module of the system must be reasonable and easy for teachers to operate, since the system is designed to improve the work efficiency and to facilitate the daily work. Last but not least, we have to fully consider the scalability and the security of the system, the information of teachers and students is restored in the system database, which is important and confidential. The leakage of information may cause a strong influence.
Information entry
The administrator will be responsible for the whole system including operating maintenance, creating accounts and inputting and updating information of students and teachers. In the proposed system, students’ information is sorted according to their grade and major. The administrator will assign each teacher an individual account as requirement. Only the administrator has right to create, alter and delete accounts and change basic information of teachers and students. The administrator will be in charge of assigning tasks to the teachers. Teachers should log in the system and finish the task assigned to. The information of the students should be updated by the administrator before a exam. Authorization set makes it easy and security for management.
Paper scanning and segmenting
The online marking system requires the students to answer the questions on a standard and proprietary answer sheet, the answer sheet should be thick-even and the size is limited by a default standard size, the column space of the answer sheet is limited as 5.08mm. Once finishing the exam, the answer sheet will be collected and converted into image format by scanning using the high-speed scanner. The processing steps are shown in Fig. 6. In the proposed system, the answer sheets are converted into RGB images by using RGB color space model, which will satisfy the need of recognition of the image. In order to provide clear images and make the reviewer more comfortable, in the proposed system, a necessary procedure is image pre-processing procedure, we transform RGB images to grayscale images by using OpenCV functions, the transform formula is showed as follows:
We also compress images for the purpose of saving space and speeding up image transmission, so grayscale images are converted into binary images. The key of binarization process is the choose of threshold T, we use iterative method for seeking threshold: First, we choose the maximum image gray value Rmax and minimum image gray value Rmin, so the T is:
Then, the threshold value T divide image gray values into two groups R1 and R2, which determine average gray value μ1 and μ2 of groups respectively as follows:
Next, a new threshold T is obtained as:
Figure 6 shows the results of the original image after grayscale and binarization, which suggests that the results meet the demand.
With the help of image pre-processing procedures, we tend to provide the image to facilitate the computer to automatic identify image to handling with the objective part, and provide the image which conforms to the human eye viewing habits. The followings are the main image processing procedures with OpenCV.
Correction of the skew images: During the scanning procedure, image skewing may happen when the papers are not located at the predefined place or non-uniform stress of the paper. Hence, correcting the skew image is a necessary part to increase the accuracy of the matching algorithms.
Binary image processing: By setting proper threshold, we can convert a 256 level image into a binary image which shows not only the outline of the image but also local character of the image with a lower data size and compression.
Image filter: Image filter is expected to remove the isolated pixels because of the under normal conditions, these isolate black pixels are produced by noise or other distortions and scattered distributed in the image, so removing the isolate black pixels will help to reduce the distortions.
Image compression: In order to realize the real-time image transmission and storage, it is necessary to compress the image as long as the compressed image still to be clear. Image compression will help reduce the load of the services and save storage space.
Image segmentation: In this procedure, the image is segmented as predefined, the image generally segmented to objective part and subjective part. The segment procedure is automatic segmented by the system, while segment quality is lower than the predefined criteria need to be modified artificially.
In imaging pre-processing procedure, the image is segmented into objective part and subjective part. The objective part will be automatic recognized by the system and the scores of the objective part is restored. The subjective part will be reviewed by the teachers and the teachers fill the scores in the system. Once the scores of subjective part and objective part are given, the system will automatically calculate the total score and generate statistical analysis reports. In order to verify the reliability of the system, Certain proportion of papers were sent to the teachers who had marked the same papers again. A curve is drawn according to the difference between the two scores shown in Fig. 7, Fig. 7 shows that the system can meet the needs. The system provided personal statistics report for each student including original grade points, norm grade points, class rank, grade rank, the highest and lowest points, selection rate, accuracy, sparkle, vulnerabilities, and provide a detail report of the student. The system also provides statical results of all candidates in the exam, including test scores of all grade students in all the subjects list (according to the candidate number or total score ranking order); summary report of all grades in all subjects exam results; distribution statement of the scores in each subject and total scores of all grades in all subjects.
Conclusion
In this paper, a streamlined online marking and storage system is presented, the proposed system based on B/S structure which will provide convenient service as long as the teacher can access to the Internet so that work from anywhere is a reality anywhere. Furthermore, we have introduced some functions in OpenCV into our system, with these functions, we can segment the image of answer sheet as predefined, correct skew images and enhance low contrast images. In database design, we adopt SQL Server database as our database which can provide high-speed data storage and query. The security issues is another reason to adopt it. The proposed system has been tested in school exam, practical application result shows that the proposed system generally improves marking efficiency and it is convenient for the teachers in statistical and data analysis. In our future work, we will improve the system and ask teachers for their suggestions to make the system more convenient and become more user-friendly.
Acknowledgments
This research is partially supported by the National Natural Science Foundation of China (No. 61471260), Supported by Program for New Century Excellent Talents in University (NCET-12-0400).