581327-6 Introduction to application design

Exercise 1, autumn 2002

  1. Let's consider the information processing related to an exam. This involves student's registration for the exam, production and delivery of the list of potential attendants to the teacher and to the department's office, evaluation of the tests and storing exam results in the result register that covers all exams. Let's assume that the result register is a closed system available only for a few authorized users (e.g. the personnel of departments' offices). The input of results may take place interactively one result at a time or by loading a computer file that contains the results of the exam.

    There are many ways to carry out the processing outlined above. Some are more computerized than the others are. Outline three alternative workflows to process the exam information. Indicate the persons that are involved in the workflow, what they do and by which means (paper forms, computer forms, etc.)

    Alternative 1 - as little as possible computerized :

    Alternative 2 - "semi-computerized":
    • A student fills in a web form in the internet (the date, exam, examinator and the student's personal information)
    • The form is e-mailed to the department's office.
    • The secretary is using an application for sorting and arranging the registrations according to courses. The application generates the attendants' list (incl. social security numbers).
    • The secretary delivers the attendants' list to the teacher.
    • Teacher evaluates the test and marks the results in the list.
    • The secretary inputs the exam results in the result register one result at a time.
    Alternative 3 - as much as possible computerized:
    • A student registers for an exam through a database registration system by choosing the exam.
    • After the registration deadline, the application e-mails the attendants' list to the teacher and to the secretary.
    • The teacher uses an electrical form in registering the results in the database
    • Teacher confirms and saves the completed evaluation.
    • The secretary receives a message of the completed evaluation by e-mail.
    • The secretary uses an application to generate a file that contains the results of the exam
    • The secretary inputs the results in the result register by loading a computer file that contains the results of the exam.

  2. Evaluate the benefits and drawbacks of your alternatives for task 1. Consider, for example, possibilities for errors, amount of work, skills needed, and equipment needed. Are some of the choices more suitable for exams with only a few students or do they suit well also for exams of a couple of hundreds of students.

    Alternative 1:

    • Errors can occur in differents phases: student, secretary, teacher, secretary
    • Laborious for the student and especially for the secretary, easy for the teacher.
    • Location-dependent: the student must come to get the form in person
    • No need for special skills
    • Modest equipment requirements: the student and the teacher both need a pen, only the secretary needs a work station
    Alternative 2:
    • Saves the secretary from the laborious sorting and arranging of the forms (especially tedious if the exam is big).
    • Location-independent: the student doesn't need to come to fill in the form in person
    • No registrations are lost in sorting and arranging forms
    • The student needs a work station and a web browser.
    Alternative 3:
    • All the correct exam data is saved in the database and the student only chooses an exam - reduces errors in the exam data. (The student can of course still register for a wrong exam.)
    • Reduces mistakes in the social security numbers
    • Speeds up the work.
    • The teacher must know how to use the application.

  3. Object oriented model of systems considers the systems to function relying on the co-operation of independent objects. Objects co-operate by using services of other objects. In this task we try to describe a (business)process as a co-operation of objects. Select one of your alternative workflows for task 1. Identify the objects involved in it and assign them services to establish the co-operation. You may select people and information systems as objects. People's services are tasks that they perform. You may think that an object uses a service of another object by issuing a request to the other object. There may be a form or any other kind of information (message) attached to the request.

    Let's consider the alternative 1:

    • Student
      • registration (student's task)
    • Secretary
      • receiving registration forms
      • sorting and arranging the forms
      • preparing the attendants' list
      • sending/ delivering the attendants' list
      • registering the results
    • Teacher
      • receiving the attendants' list
      • marking the results in the list
      • delivering the results to the office
    • Result register
      • registering the results

  4. Pizzeria Alfonso provides a pizza taxi service. No computers are used in processing the orders. Try to figure out what persons are involved in the delivery process (from placing the orders to registration of payment). and what tasks they carry out. Which tasks involve data processing? What kind of data processing?

  5. We start developing a computerized information system for Alfonso's pizza taxi service. Identify the stakeholders for the system and their information needs. Consider also other stakeholders than the ones directly involved in the process. (Stakeholders consist of people, organizations or another information systems that use or provide data for the system.)

laine@cs.Helsinki.FI