Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

Storyboard

Learnability

Efficiency

Safety


Bob launches the smart grid application and views the daily consumption for today (March 12th)
Looking at the graph he notices that his energy consumption was extremely high between 12pm and 3pm.


 

Pros:
The application provides an intuitive way to view the daily consumption. The graph makes it easy to see the power consumption throughout the day. 

The application presents the user with the option to view the monthly and yearly consumption by clicking the tabs on the bottom of the screen. In addition, the user can view the consumption for a specific device by clicking the device drop down list and selecting the device. These features are easily accessible to the user and the user is not required to click through different screens to discover these features.

Most of the features the application provides are presented to the user, enabling the user to easily explore and discover the various features the application offers.

Cons:
There is no way to overlay the consumption pattens of multiple devices, which would enable the user to easily compare the consumption patterns of different devices.

New users may be overwhelmed and confused by all the features presented on this main screen.

New users are more likely to misinterpret the data presented by the graph, not knowing that the different tabs enable them to view different data. 

Pros:
The tabs enable the user to view consumption patterns and pricing information for different devices on different dates. The user can easily access these features without having to click too many buttons or menus.

The user can easily access most of the features of the application without having to go to different screens. The user has quick access to most of the features.

Cons:
Since there is no way to overlay the consumption patterns of multiple devices, the user would have to work hard to compare the usage or consumption patterns of different devices.

Pros:
There is no way to make irreversible data-related errors on the main screen.

Cons:
The different tabs allow the user to change the display different data. Since the tabs change the mode of the displayed data, the user can easily make mode and description errors, such as viewing the information of the wrong device or clicking the wrong tab (looks similar to the other tabs). The ability to view different types of information for different devices with a single click, makes them more likely to forget which mode they are on.

There is no way to undo view actions, such as tab change.


Bob clicks the device list, which lists the available devices sorted by their energy consumption on march 12th, where the top item is the highest consumer. He selects the first item on the list, A/C1, which is one of the air-conditioning systems in his house.

The list above is an expendable list that has two groups, Consumers and Generators. The Consumers group contains all the appliances that consume energy and the Generators group contains all the appliances that generate power. The All option enables the user to view the total energy consumption or usage of all the appliances together. Clicking the group headers toggles between showing and hiding the items in the group (i.e. clicking the Consumers header once hides all the items in the Consumers group. Clicking again displays the items in the group.).

The list is sorted by energy consumption during the time frame that the user chose to view. For example, changing the date causes the list to be ordered by the consumption during the day of the selected date. Changing the view to display consumption by month orders the devices by monthly consumption. The items in the Generators group are sorted by the amount of power they generated.

The user can search for a specific appliance by typing its name into the dropdown textbox.

Pros:
Viewing data for different devices is easy to discover.

A new user attempting to find the most energy consuming devices is likely to click the device list in order to go through the different devices to find the ones that consume a lot of energy. By clicking the list and reading the label at the top of the list, the user quickly discovers that the list is ordered by consumption.


Cons:
The user has to click the list and read the label at the top of the list to discover that the list is sorted by consumption. Figuring this out could take a while, since users often do not read labels.

Pros:
The user can easily find the source of high energy consumption, since the list is sorted by power consumption.

The grouping of the appliances enables the user to easily distinguish the consuming appliances from the energy generators.

Cons:
A large number of devices may require the user to scroll and scroll and scroll, in order to get to a specific device.

The appliances are not grouped by their type, making it more difficult for the user to find all the appliances of a specific type (e.g. all ovens).

Pros:
No serious (irreversible data errors) errors can be made.

Cons:
The interface is more likely to cause mode errors as described above (in the previous section).

There is no way to undo selection choices, which can be annoying in cases where the list contains a large number of appliances, requiring the user to scroll down a lot.


The graph changes, displaying the total consumption for A/C1 on March 12.
Looking at the graph, Bob learns that A/C consumes a lot of power in the afternoon.

Pros:
The interface provides an intuitive way to switch between different data views.

The graph makes it easy to see the continuous change in energy consumption or usage.

Cons:
New users may find the tabs a bit confusing.

Pros:
The user can easily view different graphs for different types of data. All it takes is a single click.

Cons:
The graph displays the data for one appliance at a time or for all the appliances combined. There is no way to view and compare the consumption or usage data for multiple appliances by overlaying their plots.

Pros:
No serious (irreversible data errors) errors can be made.

Cons:
As mentioned above, the interface is more likely to cause mode errors.

There is no way to undo selection choices.



To see whether the additional power use is costing him much money, Bob looks at the current price information being provided by the grid by clicking the Pricing Info tab. He finds that it is a peak usage time and that prices are high.

Pros:
The interface provides an easy and intuitive way to the pricing information, accessible from all the different data view modes. New users can easily access this feature without getting lost.

The graph view provides a clear way to view the pricing info, even for new users.

Cons:
The pricing info does not depend on the selected appliance. This can be a bit confusing, since the other data graphs display appliance specific data.

Pros:
The interface provides a quick way to access the current price information from all view modes (i.e. it always requires a single click without going to a different screen).

Cons:
There is no way to view the price information as a table.

There is no way to overlay the price information for different days or months.

Pros:
No serious (irreversible data errors) errors can be made.

Cons:
As mentioned above, the interface is more likely to cause mode errors.

->
Bob decides to change the conditioner's set point. He clicks the "Config Device" button to edit the settings of A/C1. A/C1's settings screen enables Bob to edit the set point.
Bob increases the set point from 75 degrees to 80 degrees and clicks the OK button.

Pros:
The interface provides an intuitive way to access the settings of the selected device.

Cons:
Can confuse new users who want to edit the settings of a specific device, but do not care to view its consumption or usage information.

Pros:
The device settings are easily accessible from the main screen.

The device selection list and the Device Settings button are close to one another.

Cons:
The user has to access the device specific view (i.e. select the device from the list) in order to be able to edit its settings.

Pros:
Setting the set point too high or too low may result in too much energy consumption or overheating or over-cooling the house or office.

Cons:
As mentioned above, the interface is more likely to cause mode errors (such as viewing the settings for the wrong device).


Bob checks the status of his solar panels, by clicking the device list and selecting the Solar Panels option.
 

Pros:
Same as above (see row 2).

Cons:
Same as above (see row 2).

Pros:
Same as above (see row 2).

Cons:
Same as above (see row 2).

Pros:
Same as above (see row 2).


Cons:
Same as above (see row 2).


Bob checks the generated power information by clicking the Power tab below the graph. The app displays a graph showing information about the power generated by the solar panels. He decides to sell some power back to the utility company, so he clicks the Sell Power button.
 

Pros:
The interface provides an easy and intuitive way to the generated power information, accessible from all the different data view modes. New users can easily access this feature without getting lost.

The graph view provides a clear way to view the generated power info, even for new users.

Cons:
New users may find the tabs a bit confusing.

Consumer appliances and Generator appliances do not have the same view options. New users may find this a bit confusing.

Pros:
Quick and easy access to the generated power information.

Cons:
There is no way to overlay the energy generation patterns for multiple devices (the user views only one at a time).

Pros:
No serious (irreversible data errors) errors can be made.


Cons:
As mentioned above, the interface is more likely to cause mode errors (such as viewing the settings for the wrong device).

Mode errors may cause the user to make the wrong decisions (such as scheduling transaction for the wrong generator after viewing the graph for the wrong power generator appliance)


The app displays the Sell Power screen, showing a list of all the future transactions scheduled to sell extra power generated by the solar panels.
Bob creates an additional transaction by clicking the +add button.

Transactions can also be edited and deleted. The user can edit a transaction by clicking it (clicking the list item representing the transaction). 

The dropdown on the top right corner enables the user to view scheduled transactions for different devices. The user can change the device for which they view and schedule transactions by clicking the dropdown and selecting a different device. The dropdown only lists Generator appliances (e.g. solar panels or power generators)
 

Pros:
The interface resembles the android phone's alarm clock setting interface.

Cons:
Users who are unfamiliar with this type of interface may find this a bit confusing, especially editing.

Pros:
Quick and easy access to the different Generator appliances, without having to go back to the main screen.

The interface also provides a quick and easy way to create and edit transactions.

Cons:
A large number of future transactions make it difficult to find the right transaction to edit (requires a lot of scrolling).

No way to copy transactions from one device to another.

Pros:
The users can view the scheduled transactions and correct any scheduling errors.

Cons:
As mentioned above, the interface is more likely to cause mode errors (e.g. scheduling transactions for the wrong generator device).

Users may accidentally schedule transactions for the wrong time.

Such errors may result in higher costs (e.g. selling too much energy during peak hours when consumption and prices are high).

No undo/redo.


The app displays a dialog that enables Bob to schedule the transaction. Bob creates a transaction scheduled to take place at 4pm (an hour into the future). He sets the start and end time by clicking the time fields and setting the time. Then he saves the transaction by clicking the OK button and closes the application.
 
The interface above enables the user to edit the start and end time by editing the date and time fields. When the user clicks on a date or a time field the application displays a date and time dialog allowing the user to set the date. The user can specify how much power to sell by entering the amount of power to sell into the textbox at the top of the dialog.

Pros:
The interface provides a convenient way to edit the start and end date and time of the transaction. It resembles calendar event editing interfaces (the event editing dialog or screen), where the user can change the start and end time.

Cons:
Users who are unfamiliar with these types of interfaces may find it confusing.

Pros:
The interface provides a quick way to set the start and end dates and times of the transaction.

Cons:
There is no way to enter duration instead of end date and the user may have to compute the end date as a result.

The interface requires the user to exit the transaction dialog in order to be able to edit a different transaction or a transaction for a different device.

The interface provides no way to view the other scheduled transactions while adding a transaction.

Since this interface is not presented on the main screen, the user cannot view power generation information while scheduling a transaction, meaning that the user is required to remember roughly how much energy is generated in order to schedule transactions that make sense.

Pros:
The interface only enables the user to enter valid dates (date and time dialogs do that).


Cons:
The interface provides no undo mechanisms.

The user has no way to recover deleted events.

Scheduling transactions for the wrong time or date may result in selling too much energy at the wrong time of the day, which may require the user to pay for energy from external sources during peak hours, instead of using their own personal power generator or battery.

Critiques of the overall design

Pros:
Most of the features are accessible from the main screen, making them easy to discover.


Cons:
New users may be confused and overwhelmed by all the features on the main screen of the application.

Pros:
Quick and easy access to most of the features.

Cons:
The user can easily view usage and consumption patterns for each device separately, but there is no easy way to compare the usage patterns of different devices.

Pros:
The interface validates the user input.

Cons:
The interface provides no undo mechanisms.
The similarity between the different views and the way to switch between the different views may cause description errors.
Using combinations of different groups of tabs to control the data views (mainly the graphs) may result in mode errors.

...

Storyboard

Learnability

Efficiency

Safety


Figure 3.1. When Bob opens the Smart Grid application, he sees a graph of his usage for today. By touching the "month" tab at the left of the graph and looking at the average at the top right, he sees that his usage for today is much greater than his average usage over the past month. He returns to the "day" tab of the graph and notes, by expanding the tree in the bottom pane, that his air conditioner is consuming most of the power. He unchecks the boxes for all devices except for the air conditioner, which updates the graph to show only the air conditioner's power usage for the day. By doing so, he sees that the highest usage was during the afternoon.

Pros: 
The tabbed display is a familiar paradigm, especially on mobile devices.

The expandable tree used to display the devices is also familiar from other applications.

The graph is intuitive to use, and tabs, titles, and axis labels make clear what information is being displayed.

Cons: 
The use of the checkboxes in the lower pane to update the graph may be unintuitive.

It may be unclear what the usage numbers in the bottom pane correspond to: are they the current usages? averages for the day? Additional labels would be helpful to disambiguate this information.

Pros: 
The opening screen is easily glanceable. The information likely to be most important to users, the current power usage, is displayed immediately when the application is opened.

The organization of devices into a tree allows the interface to scale well, efficiently supporting operations on large numbers of devices.

Cons: 
The user may have to check and uncheck many boxes in order to display the desired information in the graph.

The device list cannot be sorted by power consumption; some exploration of the tree may be required in order to determine which devices are using the most power.

Pros: 
It is clear how to undo actions in this pane, such as checking a box or selecting a tab.
Cons: 
There are no irreversible data-related errors to be made in this view.


Figure 3.2. Bob touches the "grid" tab to view today's pricing information. Simply glancing at the shape of this graph allows him to tell it is a peak usage time. The current price is displayed on the "grid" tab, and can also be viewed by touching the current time on the graph itself.

Pros: 
The graph view and split-pane interface of this screen is internally consistent with the others.

Cons:
The application requires some background knowledge about the way the grid operates and the way power is priced. Non-expert users without such background knowledge may find it difficult to understand the information presented without more context.

Pros:
The pricing information is easily glanceable. The information most likely to be useful, the current price of power, is visible both on the graph and at the top of the tab.


Cons: 

Pros:
Cons:  There are no irreversible data-related errors to be made in this view.



Figure 3.3. To change the settings of his air conditioner, Bob first navigates back to the "usage" tab (Figure 3.1), then clicks the "settings" button for the air conditioner. The top pane displays a graph of the air conditioner's power usage for today, helping Bob decide what settings to change in the bottom pane. He uses the spinner to increase the setpoint of the air conditioner. He then presses "save" and is returned to the screen in Figure 3.1.

Pros: 
The spinners used for numeric data entry are standard Android widgets, familiar from other applications.

Spinners are populated with default values, which, together with the up and down arrows, make clear what kinds of inputs are permitted.

Cons:
By using spinners to change device settings, the application may lose external consistency with the way those settings are entered on the devices themselves.

Pros: 
The graph is automatically updated to display daily view, which is presumably the information that is most relevant to the settings being changed.

After the settings are saved, the graph returns to displaying the data that was previously selected.

Cons:
It is not possible to view data for other devices while changing the settings of a device. If the user wants to take this information into consideration, they will have to go back to the main usage screen to see it.

Since the graph is automatically updated to the daily view, if the user was interested in looking at usage over the last week or month, they will have to readjust the graph after entering the settings screen.

Pros: 
The "cancel" button allows the user to revert any changes they have made to the settings.

Cons: 
There is no indication of whether the settings have been modified, so a user may end up saving an inadvertent change.


Figure 3.4. Bob checks the status of his power storage device by touching the "storage" tab. He glances at this screen to see both the current amount of stored power and the historical amount of stored power for today.

Pros:
The graph view and split-pane interface of this screen is internally consistent with the others.

Cons: 
As with the "usage" screen, the checkboxes may be unintuitive to use, and the numbers displayed in the devices list may be ambiguous without additional labels.

Pros:
This screen, too, requires only a quick glance to determine the needed information.

Cons:
As with the "usage" screen, devices are not sorted by amount of stored power, and much checking of boxes may be needed to display the desired information.

Pros: 
It is clear how to undo actions in this pane, such as checking a box or selecting a tab.
Cons:  There are no irreversible data-related errors to be made in this view.


Figure 3.5. To schedule a sale of power, Bob returns to the "grid" tab (Figure 3.2), then touches the "schedule transaction" button. He uses the spinners to adjust the time and the amount of power to be sold. He uses the pricing graph in the top pane, and the total amount of stored power displayed on the "storage" tab, to help him decide. He touches the "save" button and is returned to the screen in Figure 3.2, which now lists the scheduled transaction.

Pros: 
Again, the use of spinners is familiar from other applications, and makes clear the kinds of inputs which are allowed.

Cons: 
The interface does not expose all underlying details of the grid and of power transactions. A non-expert user may not know how to decide on the parameters of a transaction, and may not understand where the power goes or how they are paid for it.

Pros: 
The data displayed at the top of the "storage" tab allows the user to decide how much power to sell without having to switch back to that tab.

Cons: 
Previously scheduled transactions cannot be viewed from this screen. If the user wants to take this information into account, they will have to return to the main grid page to see it.

Pros: 
Transactions take place at a scheduled time rather than happening instantly, so they can be modified or cancelled in case an error is made.

Cons:
The user receives no suggestions about how much power to sell or when to sell it, so a non-expert user could make a poor selling choice.

Critiques of the overall design

Pros: 
The similarity of each pane of the application provides internal consistency, enhancing learnability.

The use of familiar widgets and paradigms, such as tabs, spinners, trees, and graphs, provides external consistency.

Text labels clearly show what data is being displayed, and help the user understand the results of their actions.

Cons: 
Where labels are absent, the meaning of data may be ambiguous.

Certain controls, particularly checkboxes, may be hard to learn or unintuitive.

For some actions, users need knowledge of the underlying grid system beyond what is provided byt he by the application itself.

Pros: 
- The design attempts to display enhance efficiency by displaying the most relevant data for the current decision being made.

Cons:
- no consolidated view of all data
- annoying to user if automatically- If the automatically selected view is not the one that is desired by the user, this feature may be annoying rather than helpful.

There is no way to combine data from different tabs in a single view. For instance, power usage and stored power cannot be viewed together in a single chart.

Pros:
- The use of tabs, widgets, and transaction scheduling makes it clear how to undo most actions.
 
- The use of input widgets prevents spinners for input helps to prevent invalid inputs.

Cons: 
- lack The absence of suggestions from the application means may mean that non-expert users may make poor decisions.