Home > Articles > Software Development & Management > Object Technology

Designing with Idiom

  • Print
  • + Share This

3.4 Early Work with Users and the Domain

Seven mutually informing activities take place in parallel during the early stages of the design: user categorization and profiling activities, scenario generation, building of a relatively coarse-grained task model, task description and referent identification, early domain modeling, generation of design sketches, and generation and evaluation of low-fidelity prototypes. User categorization and profiling is not discussed except for a consideration of its consequences in Sections 3.4.2, 3.4.5, and 3.5.1, and low-fidelity prototypes are not discussed, except for a brief mention in Section 3.6.2.

Throughout much of the early design activities, there is a strong emphasis on opportunistic design practice while seeking to avoid over-commitment to early design artifacts. Some of the early design activities are concerned with finding visions and paths for the design—sometimes by looking in detail at the real world and sometimes through the formulation of tentative and partial design solutions that might be very concrete in nature. Subsequent early design activities abstract away from these details. Later, in Section 3.5, the resultant abstract models are used to systematically develop aspects of the user interface design. The processes of abstraction and subsequent model-based design can help in avoiding the retention of early concrete design ideas that might limit the concrete user interface design. In practice, this process must, at the least, be accompanied by user evaluation of the developing design.

Early on, it is often a challenge to formulate abstract descriptions; sometimes it is easier to adopt the design tactic of formulating a description that includes some less than desirably abstract detail, and then to remove the non-abstract detail.

3.4.1 Scenario Generation

In Idiom, scenarios are stories, natural language descriptions of use of the system, written in user terms and language. Since scenarios are expressed in user language, they may be written, reviewed, and modified by both users and designers. Scenarios can be constructed for identified types of users, or scenario data can inform the identification of user types in user profiling activities. Scenarios can be written to capture user goals, expectations, and some of the context in which the users work. Scenarios can also be used for requirements capture, for illustration and visualization of system use, and to facilitate communication between designers and users. Later, in a process of abstraction away from the concrete detail of scenarios, the scenarios provide data that is used in task modeling and referent identification. More generally, scenario generation and task modeling and description are all mutually informing.

Much of the subsequent chat example is centered around a simple scenario depicting the initiation of a conversation, shown in Figure 3.3. Some of the detail in this (monitoring the agreement of invitees) changes as the design progresses.

Figure 3.3 A scenario illustrating conversation initiation

3.4.2 Coarse-Grained Task Modeling

Idiom approaches the functional side of system specification via an abstract coarse-grained (or high-level) task model that is constructed with the users' goals in mind. A task model is required for each category of user. The level of abstraction utilized within at least the top-level tasks is similar to that of essential use cases—a kind of task model that is free of technology and implementation detail [Constantine and Lockwood 1999] (and see also Chapter 7). As with OVID [Roberts et al. 1998, p. 62], Idiom is not prescriptive as to the notation used for task modeling. Simple textual task decomposition styles are effective for both abstract and more detailed task models. One such style is used throughout this chapter. Collins [1995] recommends a similar, but slightly simpler technique that does not incorporate some of the control structures used here.

For the chat example, a simple high-level task model for a user who communicates with other users is shown in Figure 3.4. This is a rendition of a particular stage in the development of the model, along with comments, introduced with //, to the author and readers. The top-level task, Communicate, is motivated by the user goal to communicate with other users. Some sub-tasks that help realize this goal, such as address book–related tasks, are not included in the model in order to simplify and reduce the size of the example. Similarly, the task model omits the consideration of many exception conditions, such as everyone else leaving a conversation. The high-level task model in Figure 3.4 was constructed with extra detail that was then removed, as suggested in the preamble to Section 3.4.5 The scenario in Figure 3.3 illustrates the InitiateConversation and RespondToConversationInvitation tasks in Figure 3.4.

Figure 3.4 Coarse-grained task model

A key to successfully using a textural form like the task model in Figure 3.4 is to accept some degree of informality in indicating interleaved task flow and thereby gain a way of indicating unordered sequences of optional activities while still using a relatively tractable syntax. The third (loop...) and fourth (start or resume...) lines in Figure 3.4 express a user-driven choice of interleaved concurrent task execution, as might be performed by users in a modern windowed environment with different windows providing different task execution contexts. Beyond this, there is no task model consideration of the sequencing of interleaved tasks, such as communicating with two sets of users via two different and simultaneously ongoing conversations.

As in Idiom94, task models can incorporate the notion of system feedback, as in

                                   choose and invite participantsfeedback

This is similar to user action notation's (UAN's) use of an exclamation mark [Hartson et al. 1990, Hix and Hartson 1993].

3.4.3 Interaction Exploration Using Sequence Diagrams

UML interaction diagrams (sequence and collaboration diagrams) are normally used to illustrate use cases and depict details of inter-object interaction within the object model [Booch et al. 1999]. As noted in Section 3.2, while very useful for software engineering purposes, the documentation of internal object interactions is not generally useful for interactive system design (Constantine and Lockwood also note this in Chapter 7).

However, sequence diagrams can be used to visualize and illustrate interaction between users and a system. This technique is experimental; it seems useful as a way of selectively visualizing and exploring some aspects of user interaction. UML sequence diagrams that depict user-system interaction can be drawn at a high level of abstraction, or they can have increasing amounts of detail added to them. At a high level of abstraction, with both user and system actions illustrated by message sends as in Figure 3.5, the notation is close to essential use case notation [Constantine and Lockwood 1999] (and see also Chapter 7).

figure 3.5 Sequence diagram showing the initiation of a conversation and the associated issuing of invitations

The addition of task information to sequence diagrams can be useful in the visualization of the developing task model. Here, these sequence diagrams tend to show only one user, by reflecting the single-user nature of task models. Examples are illustrated in Figures 3.6 and 3.7. The advantages of such task-sequence diagrams seem to be that they do the following:

figure 3.6 Task-sequence diagram for a response to a conversation invitation when already online

figure 3.7 Task-sequence diagram for online connection to the chat system and a response to a pending conversation invitation

  • Combine user tasks with depictions of interactions between the user and the system, and thereby start to "bring the task model to life" as part of the developing user interface and system design.

  • Help in the examination and further development of the envisioned task model.

While this diagramming technique can be used to illustrate increasingly fine-grained task models, indications are that the point at which to stop this activity is when the high-level task model has been satisfactorily explored. However, since sequence diagrams are notationally heavyweight and have only limited applicability for high-level system visualization purposes, they may either be omitted from future versions of Idiom or only be used for occasional task-model visualization. Certainly, the technique would be tedious and time-consuming in use at fine-grained detail for large systems, or even all the way across a set of high-level tasks.

3.4.4 Describing Tasks and Identifying Referents

Users have goals that they attempt to realize by task performance. During task performance, users manipulate referents, which are user-world objects that are of interest or utility to users in the performance of their goal-directed task behavior. (See the CHI97 framework in [van Harmelen et al. 1997] or see Chapter 10.) Idiom encourages the discovery of referents from scenario data as part of the process of extracting task descriptions from scenarios. These referents are later represented by types and attributes in the domain and core models and are used in the identification and design of a set of contexts for task execution to be implemented in the interface.

The procedure for describing tasks and recording referents in Idiom is to list selected tasks defined in the task model, to describe these tasks in user language (some of this detail may appear in enacted form in the scenarios), and then to find and describe the referents used in each task from the task description. Referents appearing in the task description are underlined and are listed after the task description. Focusing on nouns in the task description is one good way to find potential referents. Each referent description includes (a) a resolution of any naming ambiguities in the task descriptions (if those ambiguities have not, for one reason or another, already been resolved) and (b) a user language description of the referent.

In Figure 3.8, a task has been rendered as a brief textual description; the underlined words refer to objects or relationships. Referents used in the task are listed below the task, together with a resolution of any ambiguities in terminology, the chosen names being unbracketed. Not all of the extracted referents are model objects in themselves. For example, invitee status could be represented in a domain or core model using a UML-association class, or by the use of different associations, as shown in Figure 3.9; the former is the more elegant solution.

Figure 3.8 A task description together with referent descriptions

Figure 3.9 Modeling invitee status (with the preferable solution on the left)

This phase of referent identification is not the only source of referents. Scenarios and business input may provide referents, as may users, domain experts, and designers. Whatever the source, referents should be recorded against the task descriptions in which the referents are used. This information will be used to discover if any task execution contexts can be merged during later user interface design (see Section 3.5.3.1).

3.4.5 The Domain Model

The domain model uses referent types to represent referents in the users' world and uses associations to represent relationships between those referents. First versions of the domain model should be developed as soon as possible to encourage the designer to rapidly understand the contents and structure of the application domain. Skilled object modelers may wish to start modeling almost immediately, using the later output of the referent identification as an additional source of information for their modeling activity, while less experienced object modelers may wish to start modeling only after the referent identification has produced some output, without worrying too much, at first, about cardinalities. Whichever approach is taken, the domain model must articulate the users' understanding of the domain before the core model is constructed (see Section 3.5.1).

Should users be modeled in the domain model? A domain model for an architectural CAD system would not include the users of that system [van Harmelen 1994]. However, in systems in which users need to communicate and interact with each other, users appear in the domain model. However, it should be noted that modeling provides only a very abstract representation of interactions between users; modeling is no substitute for field work that leads to a rich understanding of ways in which the user activity can be supported.

The chat example includes users who communicate with each other. For these users, initial referent identification leads to the model shown in Figure 3.10(a). Figure 3.10(b) shows a slightly enlarged domain model incorporating another referent—an address book or "buddy list" that provides referents for use while initiating a conversation.

Figure 3.10 (A) Basic domain model and (B) the domain model used later in this chapter

Different types of users may use different kinds of referents in distinct domain models. Thus, if there were chat system administrators who were responsible for chat server administration, their domain model would have to include referents representing servers and provide operations on those types to enable and support the administrators' activities. To accommodate different kinds of users, designers can think in terms of different compatible domain models, or in terms of different aspects of a single domain model.

3.4.6 Visualization Using Sketches

There is a strong need for the users and designers to gain a feel for a system, and how it might operate, very early in design. Sketches—freehand drawings of the system's appearance—can be used to depict user interfaces while exploring system functionality, behavior, and use. The process of drawing sketches by hand is direct and immediate, without the overhead of computer use. Sketches can be combined to form storyboards, which are sequences of depictions of the system over time, or interaction sequences [van Harmelen 1994], which are sequences of renditions of the screen state separated by depictions of user interactions that cause the transitions between the renditions, see Section 3.6.1. For user interface design, sketches can include ideas of interaction along the lines of the example shown in Figure 3.11. All of these sketching techniques provide user interface representations that can be discussed, compared, mutated, redrawn, and even used as prototypes, all without any need for polished drawing skills. As such, the technique is simple, useful, and laudable. Winograd [1995] makes some similar observations about sketching for software design.

Unfortunately, there is a danger that, as an early design activity, sketching can lead to (a) inappropriate assumptions on the part of the designers and (b) incorporation of premature and inappropriate low-level interaction detail into the developing design. Once recorded in an early sketch, there can be a strong tendency for ideas of system appearance, interactive characteristics, and functionality to continue unrevised in the developing design. As pointed out by Constantine [2000], avoiding these problems is a good reason for proceeding directly to an essential view of the system. Idiom's approach involves retaining sketching and early concrete visualization while being aware of their limitations.

The original version of Figure 3.11 was drawn on a whiteboard within an hour or two of starting this design study. The figure provides examples of the kinds of problems that early sketches can introduce:

Figure 3.11 Rough early design ideas about interaction flow copied from a sketch on a whiteboard

  • Inappropriate assumptions: The rendition uses, to a computer-literate designer, a useful interaction technique that allows for revision of choices while formulating a list of conversationalists. Interestingly, in showing just how wrong designer choices can be, the very first user who was asked how to initiate conversations rejected this approach in favor of manipulating (in some unknown way) photographs of the users with whom he wanted to chat. 6 Yet other users might want a shortcut in order to chat with a single online user.

  • Sub-optimal concrete design choices: The status window was soon abandoned as polluting the view space, because, if it were needed, the status of conversationalists (accepted, refused, not online) could be shown in each user's chat window, given a likely-to-be-found solution to the problem of displaying invitee status for a set of invitees.

Even with the danger of these kinds of problems, sketching is extremely valuable and can be used effectively if designers are prepared to revise solutions. Involving users, working with user-derived information in the design process, abstracting and then using the resultant models in further design, and testing prototypes with users are all ways of encouraging suitable revision while gaining a deeper understanding of and feel for the developing interactive system design.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020