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This paper addresses the issue of exam paper evaluation using neural network. This paper foresees the possibility of using adaptive real time learning through computers viz. the student is made to feed his answers in a restricted format to the computer to the questions it puts up and the answers are evaluated instantaneously. This is accomplished by connecting the computers to a Knowledge Server. This server has actually connections to various authenticated servers (encyclopedias) that contain valid information about all the subjects. The information in the server is organized in a specific manner. The exam is adaptive in the sense that the computer asks distinct questions to each individual depending upon their specialization. This paper also analyzes the role of existing neural network models like Adaptive Resonance Theory (ART), Back Propagation, Preceptor; Self-Organizing Feature Map (SOFM) can be optimized to implement such an evaluation system.
Computers have revolutionized the field of education. The rise of internet has made computers a real knowledge bank providing distant education, corporate access etc. But the task of computers in education can be comprehensive only when the evaluation system is also computerized. The real assessment of students lies in the proper evaluation of their papers. Conventional paper evaluation leaves the student at the mercy of the teachers. Lady luck plays a major role in this current system of evaluation. Also the students donâ„¢t get sufficient opportunities to express their knowledge. Instead they are made to regurgitate the stuff they had learnt in their respective text books. This hinders their creativity to a great extent. Also a great deal of money and time is wasted. The progress of distance education has also been hampered by the non-availability of a computerized evaluation system. This paper addresses how these striking deficiencies in the educational system can be removed.
2. Conventional Evaluation System
The evaluation system at present involves the students writing their answers for the questions asked, in sheets of paper. This is sent for correction to the corresponding staff. The evaluator may be internal or external depending on the significance of the exam. The evaluator uses the key to correct the paper and the marks are awarded to the students based on the key.
2.1.1. Evaluatorâ„¢s biasness:
This has been the major issue of concern for the students. When the staff is internal, there is always a chance for him to be biased towards few of his pupils. This is natural to happen and the evaluator cannot be blamed for that.
2.1.2. Improper evaluation:
Every evaluator will try to evaluate the papers given to him as fast as possible. Depending on the evaluation system heâ„¢ll be given around ten minutes to correct a single paper. But rarely does one take so much time in practice. They correct the paper by just having an out look of the paper. This induces the students to write essays so that marks can be given for pages and not for contents. So students with real knowledge are not really rewarded.
2.1.3. Appearance of the paper:
The manual method of evaluation is influenced very much by the appeal of the paper. If the student is gifted with a good handwriting then he has every chance of outscoring his colleagues.
2.1.4. Time delay:
Usually manual correction takes days for completion and the students get their results only after months of writing exams. This introduces unnecessary delays in transition to the higher classes.
2.1.5. No opportunity to present studentâ„¢s ideas:
The students have really very little freedom in presenting their ideas in the conventional system. The student has to write things present in his text book.
3. Proposed System
Having listed out the demerits of the current evaluation system, the need for a new one becomes the need of the hour. This proposal is all about computerizing the evaluation system by applying the concept of Artificial Neural Networks.
The software is built on top of the neural net layers below. This software features all the requirements of a regular answer sheet, like the special shortcuts for use in Chemistry like subjects where subscripts to equation are used frequently and anything else required by the student.
3.3. Neural Network - Basics
An Artificial Neural Network (ANN) is an information processing paradigm that is inspired by the way biological nervous systems, such as the brain, process information. The key element of this paradigm is the novel structure of the information processing system. It is composed of a large number of highly interconnected processing elements (neurons) working in unison to solve specific problems. ANNs, like people, learn by example. An ANN is configured for a specific application, such as pattern recognition or data classification, through a learning process.
A Simple Neuron
3.4. Basic Structure
The examination system can be divided basically into three groups for each of the following class groups:
Higher secondary education
The examination system has to be entirely different for each of the above groups because of their different learning objectives. In this paper the primary education is not dealt because of its simplicity.
3.4.1. Some basic distinctions between the later two groups:
In secondary education importance should be given to learning process. That is the question paper can be set in such a fashion so that the students are allowed to learn instead of giving importance to marks. This will help in putting a strong base for them in future. Also a grading system can be maintained for this group.
In higher secondary importance shall be given to specialization. That is the students will be allowed to choose the topic he is more interested. This is accomplished by something called adaptive testing viz. the computer asks more questions in a topic in which the student is confident of answering or has answered correctly.
3.5. Organization of the reference sites:
The reference sites must be specifically organized for a particular institution or a group of institutions. This can also be internationally standardized. The material in the website must be organized in such a way that each point or group of points in it is given a specific weigtage with respect to a particular subject. This would result in intelligent evaluation by the system by giving more marks to the more relevant points.
3.6. Requirement of a new grammar:
The answer provided by the student is necessarily restricted to a new grammar. This grammar is a little different from the English grammar.
If one is to negate a sentence it is compulsory to write the Ëœnotâ„¢ before verb.
3.7. Question Pattern & Answering:
The question pattern depends much on the subject yet the general format is dealt in here.
For instance in computer science if a question is put up in operating systems then the student starts answering it point by point. The system searches for the respective points in the given reference websites and gives appropriate marks for them. The marks can be either given then and there for each of his point or given at last. Both the above said methods have their own advantages and disadvantages.
3.8. Role of Neural Network:
Tasks cut out for the neural network:
Analyze the sentence written by the student.
Extract the major components of each sentence.
Search the reference for the concerned information.
Compare the points and allot marks according to the weigtage of that point.
Maintain a file regarding the positives and negatives of the student.
Ask further questions to the student in a topic he is clearer off.
If it feels of ambiguity in sentences then set that answer apart and continue with other answers and ability to deal that separately with the aid of a staff.
A suitable algorithm like the back propagation can be used for this purpose. The use of a new neural network model designed specifically for this purpose is suggested. The neural network should be integrated with a grammatical parser which analyses the grammar.
3.8.2. Analysis of Language by Neural Network: (Substantiations that the language can be recognized effectively)
1. Preceptor learning was used for learning past tenses of English verbs in Rumelhart and McClelland, 1986a. This was the first paper that claimed to have demonstrated that a single mechanism can be used to derive past tense forms of verbs from their roots for both regular and irregular verbs.
2. Prediction of Words (Elman 1991):
Elmanâ„¢s paper demonstrated how to predict the next word in a sentence using the back propagation algorithm. The input layer receives words in sentences sequentially, one word at a time. Words are represented by assigning different nodes in the input layer for different words. The task for the network is to predict the next input word. Given an input word and the context layer activity, the network has to activate a set of nodes in the output layer (which has the same representation as in the input) that possibly is the next word in the sentence. The average error was found to be 0.177.
Figure 2 - Network architecture for word prediction (Elman 1991)
3. Non-supervised learning algorithm
Self-organizing feature map (SOFM, Kohonen, 1982) is an unsupervised learning algorithm that forms a topographic map of input data. After learning, each node becomes a prototype of input data, and similar prototypes tend to be close to each other in the topological arrangement of the output layer. SOFM has ability to form a map of input items that differ from each other in a multi-faceted ways. It would be intriguing to see what kind of map is formed for lexical items, which differs from each other in various lexical-semantic and syntactic dimensions. Ritter and Kohonen presented a result of such trial, although in a very small scale (Ritter and Kohonen, 1990). The hardest part of the model design was to determine the input representation for each word. Their solution was to represent each word by the context in which it appeared in the sentences. The input representation consisted of two parts: one that serves as an identifier of individual word and another that represented context in which the word appears.
4. Adaptive Resonance Theory
The basic idea of Adaptive Resonance Theory (ART) (Grossberg, 1980) is that to achieve a stable learning, top-down expectation connections are directed to only one direction, from the input layer towards the output layer. In ART, in addition to the connection from the input layer to the output layer, there is a connection from the output layer to the input
Layer that is used to project expectations onto the input layer. The particular architecture described here is called ART1, which learns arrays of binary data (values of each variable
Is either 1 or 0) (Carpenter and Grossberg, 1987). Original ART algorithm is defined in terms of differential equation and thus the network.
Figure 3 ART Resonance
State (neuron activities and connection weights) unfolds through time. In the following,
Figure 4: Self Organizing Feature Map
The training of the neural network is the vital part of success of this proposal. The training involves a team of experienced
Psychology cum Evaluation Masters
The subject masters train the net to have a general idea of paper evaluation. The language masters give specific training to the net to expect for various kinds of sentences. The psychology masters train the net for various levels of error acceptance in semantics. They also train the net about the common mistakes the student is expected to make in sentences. The neural network is put into a phase of supervised training for a specific time until its error margin is less than what is allowed. This beta version can be checked for common defects and improvised further according to the requirements of the students.
4.1. Effective distant education programmers
The distant education programmed at present has no effective examination system. If such a model is implemented, the distant education methodology will lead to a greater success.
4.2. Competitive exams to become more realistic
The competitive exams at present are restricted only to objective questions. This is attributed to the human factor. This situation can be changed and even descriptive questions can be asked in such examinations after the implementation of this system.
4.3. Evaluatorâ„¢s biasness, Handwriting â€œ not really an issue
Majority of the students have trouble in negotiating the above factors in any examination. This system is really a relief to all such grievances.
4.4. Freedom of ideas
The student has the liberty to write any point provided they are valid and relevant. This really was a hurdle to students as they are made to write things known to their staff or given in their text book.
The student can start his specialization early with just basics of everything. The student is just expected to know the basics by the computer say in the first round of questions. In the successive rounds of questionnaire the computer asks questions related to the topic he is much better versed in. This can seldom be expected in our conventional system. Thus it leads to early specialization with the student deciding on the topics he is to learn.
The student has to learn few basic changes in grammar.
The computer cannot be cent percent error free. There is of course some error margin but it is very little when compared to a human.
Reasoning type questions cannot be evaluated by the computer.
Subjects like Mathematics, English cannot be evaluated using this model.
6. Road Ahead
The proposal explained above can be easily integrated into a working model. This change of evaluation system results does a lot of good for students, as well is expected to change the educational system. A research on this proposal would further make the system much more efficient.