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Scenario

After getting home in the evening, Bob opens the Smart Grid application to check his overall power consumption for the day. He notes that this consumption is higher than usual. Then he checks the hourly consumption, noting that it was highest during the afternoon. To find out why, he examines the power usage of his devices in more detail, discovering that much of the power was being consumed by his central air conditioning.

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

In order to save power and money, Bob increases the set point of his air conditioning by several degrees. He also checks the status of his power storage and decides to sell some of his extra power back to the utility company, taking advantage of the peak-time prices. He creates a transaction scheduled to take place an hour in the future, saves it, and closes the application.

Designs

Design 1 - Data Wizard

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.

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.


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.

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.

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.

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

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.

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.

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.

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.

Design 2 - Data Wizard

The screen displayed above is the main screen of the application. It gives the user easy access to most of the features the application has to offer.

The user can view different types of graphs by clicking the tabs below the graph display. For energy consuming devices, the user can view a graph displaying the cost (money spent), consumption, pricing information or a combination of all three (each displayed in a different color). The view options for energy generating devices, such as solar panels, are slightly different, allowing the user to view a graph displaying generated power.  

The user can change the time frame of the displayed data by clicking the lower set of tabs, which allow the user to view data by day, month or year.

The day view (Day tab) enables the user to view daily data recorded on different dates. The user can view data from a different day by setting the date control (on the top of the screen) to the desired date.

The month view(month tab) enables the user to view monthly data. The user can only change the month and the year (not the day). When the Year tab is selected the user can only change the year and the displayed data includes all the data recorded during the selected year.

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 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 errors, such as viewing the information of the wrong device. 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 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.

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 is sorted by consumption. Figuring this out could take a while, since users often do not read labels.

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Cons:
A large number of devices may require the user to scroll and scroll and scroll.

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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.

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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.

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->
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.

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

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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.
 

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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. 
 

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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.
 

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Critics to the overall design

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