Storyboard |
Learnability |
Efficiency |
Safety |
Bob launches the Smart Grid application from his tablet. He notices from the consumption bar at the left side of the screen that the energy cost in the past 24 hours is very high - $18 - considerably higher than the average. He then uses the chart at the right side of the screen to find out that the consumption was the highest from 11AM to 2PM. He clicks on the Devices button at the bottom of the screen to navigate to the Devices view, trying to find out why.
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Pros:
The consumption bar intuitively provides information comparing today’s consumption to the historical records. It uses the metaphor of a thermometer or other similar scaling devices.
The bar chart is a common way to break down data in different time periods, so it’s easy to learn.
The radio button that allows user to select data on consumption or on cost basis is also easy to learn.
Cons:
Using different tabs for daily, weekly, and monthly data is inconsistent with most applications. A user might expect to get different types of presentation on different tabs, although they are the same with only different time scales. Putting them on one page and using radio buttons for selecting time frame would be a better approach.
The consumption bar shows cost, while the chart shows power consumption. It is inconsistent. |
Pros:
The consumption bar allows user to efficiently compare today’s data with historical data, and quickly detects any anomalies.
The chart presents much data efficiently in a small space, and yet makes anomalies stand out in a comparison way. If it further supports swiping to change time frame, it would be more efficient.
The radio button to select consumption verses cost allows quick switch between different kinds of useful information.
Cons:
The screen does not provide information on per device basis. Finding out which device causes problems requires user to dig into other screens, and thus inefficient.
Browsing the chart to a specific date and time is also inefficient. Adding a Calendar widget would remedy the problem.
It’s also not easy to compare same time period, say 1PM-6PM of different days. |
Pros:
There is generally no safety issue. If user chooses a wrong button, for example, he or she can quickly switch back. If navigates to a wrong page inadvertently, he or she can also quickly browse back.
Cons:
If user goes to another time frame in the chart by swiping, it could be difficult for him or her to get back. Adding a “Back to Today” button would fix the problem.
If user navigates back and forth between different screens, inadvertently or not, the selection he or she made needs to persist.
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In the Devices view, Bob can see the Floor Plan tab, which presents all the devices in his residence in graphics, grouped by areas as he arranged when he first setup the application. Today however he wants to see what devices consume most power, so he clicks the By Consumptions tab.
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Pros:
The floor plan naturally maps the devices as they are in the real world, and thus is easy to learn.
Using graphics for devices is also intuitive and helps learnability. Adding words or tooltip around the icons helps make information more precise.
Cons:
The device icon should not be just a static image. Clicking on it should allow user to go to the corresponding control page of the device, or view detailed energy information of the device. |
Pros:
Using graphics is more efficient than words for user to glance all the devices.
Cons:
The floor plan may not scale well to large facilities, for example, a factory. More hierarchies, and zooming capabilities would be needed in that case.
When more devices are available in one place, for example, the basement, they may not fit into the space available. This is another scalability concern with this interface. |
Pros:
Using the screen has no safety issue. If user inadvertently navigates to another screen, he or she can quickly come back.
Cons:
Using the screen has no issue. Designing the screen at the first place would need to consider safety, but it’s not in the scope of this project |
In this screen, Bob can see all his devices in a tree view, along with their consumptions in the time period that Bob has chosen at the left side of the screen. Today, he chooses 11AM to 2PM. The screen also lists the top five power consuming devices. The top of the list is the central air conditioner. Clicking on the device brings him to its control screen.
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Pros:
The interface uses radio buttons, a tree view, and a table to presents perspective information. All offer standard affordance.
If user selects a different time range, the device tree view and the consumption table immediately updates their perspective data, providing immediate feedback.
Cons:
It’s not easy to do various kinds of comparisons in this UI. For example, user can’t compare a specific device’s data on different days. |
Pros:
The device tree view allows user to tailor it according to the task on hand, by collapsing or expanding parts accordingly. This makes it efficient to retrieve information.
The Top Consumer table allows user to quickly find out which devices consume most power in a given time.
The radio buttons for time rage selection allows user efficiently see data in different time range without navigating to other screens.
Cons:
It doesn’t provide search capability. If user forgets where a device is, drilling down the tree to find it wastes time.
Individually select start time and end time using the widget provided could be inefficient. |
Pros:
If user selects a different time range by mistake, he or she can quickly correct it, by clicking it back.
Cons:
If user collapses a subtree inadvertently, it may not be easier for him or her to get back to the view before, unless the software specifically remembers it. |
In this page, he adjusts the cool setpoint of his home from 65 degree to 75 degree by clicking the up buttons at right side, and the dial at the left side provides immediate visual feedback. After he is done, he clicks the OK button.
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Pros:
The interface uses standard and intuitive controls.
The dial is a metaphor of the physical ones used in many households. It provides immediate visual feedback upon user clicks the up/down buttons.
Cons:
User may think the dial can be directly adjusted, while it can’t be.
The dial doesn’t give the precise number. Supplementing it with edit control will fix that.
While user is adjusting the set point, it’s not obvious what the current effective value is. |
Pros:
User can see the set point quickly.
Cons:
If user wants to adjust the set point by a large amount, clicking the buttons to do so is inefficient |
Pros:
User has to use the OK button to make an adjustment take effect, so the chance of error is reduced.
Cons:
If user makes a mistake and sets it to a wrong value, the UI doesn’t tell user the previous effective value to be restored to. It also doesn’t support Undo. |
Bob is curious about the price information now. So he clicks the Prices button at the navigation bar at the bottom of the screen. The Prices screen provides a chart on how much the market will pay for the power that consumer sells, broken down by hours. For comparison purposes, the chart also provides the highest and lowest records in the past. The right side of the screen provides the estimated extra power that his generators provide during the same period of time. Noticing the price from 12PM to 4PM is very good, and he has extra power, so he decides to sell some. So he clicks the Transactions button at the navigation bar
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Pros:
The price bar chart is intuitive. The “I” shape mark on top of each bar provides historical statistics data, helping user make decisions.
The storage chart provides the overall storage information. It aggregates the data from different sources, providing the third dimension of information, helping user further manages their devices.
Cons:
The price chart doesn’t allow user to adjust the timeframe.
The storage chart doesn’t allow user to choose devices.
No information is available about the historical storage data. |
Pros:
It’s efficient to use the charts to get price information, and statistics helps user make right decisions.
It’s efficient to see the storage data on a per device basis, helping users plan the use of their devices better.
Cons:
Aggregating devices in this fashion may not scale well when the number of storage devices is large.
User can’t compare the data of a specific device at different time periods.
The page doesn’t allow user to select a device and sells its power from there. User has to navigates to another page to do so. |
Pros:
The view isn’t used to get user inputs, so safety in terms of correcting wrong data doesn’t apply.
Cons:
The Storage chart uses estimated data. Decision making based on it may not be reliable. |
In the Transaction page, Bob selects the time, power source, and the amount of power he wants to sell. The Smart Grid application calculates the profit for him. After inputs the correct information, he clicks the Sell button. At the right side of the screen, the Pending Transaction table lists all the pending transactions. Bob can see the transaction he just made is listed there. He can select one or more transactions to cancel if he wants to, but that’s not the plan today. Thinking he can make $10 back, Bob is satisfied, and closes the application.
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Pros:
The form at the left side of the screen uses standard controls for user to enter a transaction.
The table at right side lists pending transactions effectively.
User can check the checkbox next to a transaction to view more details or to cancel the transaction. This is consistent with many other applications.
Cons:
No interface for user to get historical transaction data.
It doesn’t provide report capability, which should belong to this page. |
Pros:
User can quickly view all the pending transactions and the profits they will generate.
Cons:
User can only initiate a Sell transaction one source for one time period at a time. It’s inefficient to sell from multiple sources and in different time frame. |
Pros:
It allows users to cancel a pending transaction, in case they change their minds, or they initiated a transaction by mistake.
Cons:
Miss a Clear button at the left form. |
Critics to the overall design |
Pros:
The overall frame structure is sound – a navigation bar at the bottom using large icons, and the screen above provides the corresponding view. It’s easy to navigate around.
The view uses tabbed view as needed. The tabs are clearly visible and intuitive.
The UI is generally based on graphics, and thus intuitive.
It presents information in a self explanatory way.
It generally supports direct manipulation, and provides immediate visual feedbacks
Cons:
The contents seem light to fit in a large tablet screen – the charts and widgets may need to be large in order to fill it. But this remains to be seen.
Price and Transaction screens can be combined, because they provide closely related information.
If we allow user to click on a device in the Consumption screen to jump to the Devices screen to view its detailed data, user may feel the screens change abruptly. If we don’t allow such screen change, however, user may feel the screens are disconnected. The dilemma applies in general in this design.
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Pros:
Navigation between screens and between tabs is efficient.
Data is presented efficiently, and allows user to easily retrieve the information needed to make decisions.
Cons:
Some useful charts are missing from the design so far.
Data entering in some screens is inefficient.
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Pros:
The UI is generally fault tolerant. User can return to the original state if he or she makes an error.
It allows user to cancel a transaction if it’s needed.
Cons:
At some places, it only presents estimated data for user to make certain decisions, this can be unsafe.
No Undo capability in certain places where such capability would help.
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