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MADE Mobile Agents based system for Distance Evaluation. Vikram Jamwal 99329009 KReSIT, IIT Bombay Guide : Prof. Sridhar Iyer. Contents. The application Motivation Domain Existing Schemes Distributed system structuring Prevailing paradigms Mobile agent approach
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MADEMobile Agents based system for Distance Evaluation Vikram Jamwal 99329009 KReSIT, IIT Bombay Guide : Prof. Sridhar Iyer
Contents • The application • Motivation • Domain • Existing Schemes • Distributed system structuring • Prevailing paradigms • Mobile agent approach • Mobile agent frameworks • Our model • Experimentation • Conclusions
Distance Evaluation • Emergence of distance education • Need for distance evaluation mechanisms • Alternatives to paper-based exams • Computer based and Internet based • Scheduled and uniform exams
Types of e-testing mechanisms • Where does the database reside? • Locally • Computer Based Testing (CBT) • Examples • GRE and GMAT • Remote • Internet based testing • Examples • www.eexam.com • www.netexam.com • Any Time exams
Computer Based Testing (CBT) Generator Feedback Question Bank Question Paper • Different Question-Paper for each examinee • Generated dynamically • Adaptive • Different weights given to different questions • Next question decided on the basis of • difficulty level and • correctness of answer to previous question
Existing Internet Based Testing Schemes • Front End • Mostly “HTML - form based” • answers sent using ‘GET’ and ‘POST’ methods • Java applets, flash • Back End • CGI scripts • Java servlets • Security • Authentication done using ‘login - password’ • May use “https” for secure exchange • Some issues • Web Servers are basically stateless
Important Points • Existing models are basically • Pull based • Client-Server • Extending Internet based evaluation techniques • Push model • Different kinds of content • Dynamic organization of content • Off-line examination V/S on-line examination • Subjective answers (not just objective) • Key technical issues • How to deliver the exam content? • How to evaluate the answers? • Our solution • Use Mobile Agents
Distributed System Structuring Mechanisms Call to server procedure Data Client Server results Procedure Client Server Procedure Data Client Server results Remote Evaluation Data Client Server Procedure Code on Demand
Data Data Server Server Procedure + State Data Client Server Procedure + State Data Procedure + State Server Procedure + State Procedure + State Mobile Agents
How Mobile Agents Help? • Map directly to real life situations • Need a generic execution environment • Can work in both modes • push • pull • Can work off-line • Provide local interactions • Provide multi-hop solutions
Typical Mobile Agent Framework Server Laptop System Resources Data Base Desktop User Application Legacy Software Execution Environment Mobile Agent Service Agent Application Agent Migration Local Communication Global Communication
MAFs • Components • Life Cycle • Navigation • Communication • Security • Classification basis • Type of migration and code shipping mechanism • Agent tracking and directory service • Resource access control mechanism • Communication • Local, global, communicating partners • Systems Surveyed • 50+ frameworks • Notable : Aglets, Concordia, Voyager, Grasshopper, D’Agents, Mole
Voyager - Our Choice • Better remote messaging • Generalized distributed object computing platform • Compatibility with latest java version • Easy creation of remote objects • Moving objects • relative and absolute • Other • Federated directory service • Different kinds of messaging (sync, one-way, future) • Object and agent persistence support • Distributed event handling • Security manager • Compatible with CORBA and DCOM
Examination Process (Three Stages) • Exam setting • examiners set the question papers • Distribution and testing • question papers are presented to the students • Evaluation and result compilation • answers are collected and results compiled • Design guidelines • Automate as much as possible • Simplify requirements of infrastructure at different ends • Reliability
Examination Setting: Overview Comprehensive Paper PS-1 PS-2 PS-3 Paper Assembler PS-4 PS-4 To Distribution Server PS = Paper Setter = Mobile Agents
Examination Setting: Details NS Launcher Controller GUI NS = Name Server N = Paper Setter Node Fetch Agent Install Agent Cloning GUI N-1 N-2 NS NS
Dynamic Upgradation InstallAgent FetchAgent RemoteSetterGUI NamingService new RemoteSetterGUI() register( ) getGUIName() getGUIReference() new EnhancePanel() addEnhancePanel() removeEnhancePanel()
Distribution and Testing Single copy of paper List of Students enrolled … … Distribution Server Exam Center Distribution Server 1 2 c9611060 5 Each copy returned Separate Copy per user 4 Answered and Returned 3 Each Candidate get a Copy
Evaluation and Result Compilation c9611060 Objective Questions Evaluator Distributor Examiner B Distribution Server Examiner A Examiner C Examiner D Results … … Agents collaborate to produce the final result
Stage 2 and 3 : Details Examiner –2 Paper Coordinator Examiner –1 Result Publishing Server Answer Paper Agent Evaluation Center Objective Question Evaluator Question Paper Courier Agent Distribution Server –1 Distribution Server –2 Student- 1a Student- 1b Student- 2a Student- 2b
Salient Features of the Design • Generic execution environments on each machine • Remote code installation • After distribution and before collection • The students work off-line • Agent creation by distribution servers • Not student machines • Workflow between examiners • Automated compilation of results
Student Paper Interface Client MA Interactions Client –Server Interactions
Incorporating Dynamic Contents New Level Old Level • MQPs can be organized into various skill levels • Once a person has finished one level, a new level 2 can be sent
Conclusions • Mobile Agents provide effective and flexible mechanisms for structuring distributed systems like distance evaluation • Advantages • Student response times • Handling objective and subjective contents • Application level multicasting • Dynamic upgradation of applications • Support for heterogeneous execution environments • Centralized control and management of logistics and security of examination process • Some Issues • Reliability • Persistence • Security • Infrastructures