Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC

Anais do IHC’2001 - IV Workshop sobre Fatores Humanos em Sistemas Computacionais 43
switching back and forth between topics), we are now completely unconstrained (except
due to technological limitations such as memory capacity, which we will not consider
here). This can be a major source of confusion and frustration to inexperienced users, for it
does not have any parallel in human-to-human conversation.
4.4 Interaction Specifications
In order to compare the interaction in the three different environments, as specified in Dahis’
specification language, LECI, we reproduce below the specifications, where the semantic
types (shown previously between parentheses) have been omitted for the sake of clarity:
Phone ATM Web
Task
GetAccountBalanceViaPhone
sequence
{
Dialog AccountNumber
Dialog AccountPassword
Dialog AccountBalance
Dialog ServicesSelection
}
Task GetAccountBalanceViaATM
sequence
{
Dialog AccountNumber
Dialog AccountPassword
Dialog ServicesInfo
Dialog ServicesSelection
Dialog
InfoServicesSelection
Dialog VideoInfoSelection
Dialog ConfirmPassword
Dialog AccountBalance
}
Task GetAccountBalanceViaWeb
sequence
{
Dialog AccountNumberPassword
Dialog ServicesSelection
Dialog AccountServices
Dialog AccountBalance
}
From the interaction specifications, we may notice that, on the phone, the default
operation is to verify the account balance, and thus no user selection must be made. This is
probably due to the limitations of the linearity of the channel, coupled with cost
considerations. Moreover, all the services in this system are for information retrieval only; no
transactions can be made without a human attendant. In contrast, on the ATM and on the web,
a whole range of services is offered. A couple of things are worthy of comment: how user
identification was handled, how on-screen and printable versions of the information were
accessed, and how the navigation between selection options could be made.
User identification took place differently in each environment. In phone banking
and web banking, the user provided the account number, whereas in the ATM, the card
itself provided the identification. In both systems the user had to confirm his/her id by
means of a password. On the phone system, the account number and the password were
requested in two consecutive moments, whereas, on the web, they were provided at the
same interaction exchange. As soon as the identification took place, the range of possible
conversations was constrained by both user profile and technological considerations.
The forms of access to on-screen and printable versions of information also differed
between systems. On the web, the information was displayed on-screen, and the user could
print it through extra-system features of the browser. On the ATM, the user had to
prematurely choose the media in which the information should be provided. This difference
reveals an absence of an underlying high-level interaction model common to both systems.
As to the navigation structures, which somewhat reflect the dialog structures, we
find a narrow and shallow structure on the phone system, i.e. few options are presented at
once, and there are few options overall. On the ATM, we have many services options, but
due to display size limitations, few are presented at any given moment. In other words, the
ATM presents a narrow but deep structure. The web system, virtually unconstrained,
presents a wide and shallow structure, in addition to a persistent menu of services, which
provide direct access to any second-level menu in the system.