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Retours d’expériences Big Data en entreprise<br />

variations. Buildings also vary in age, with generations of local architectural adaptations made over time. Then<br />

there are the occupants — a mix of people with unique activities and comfort thresholds. Understanding how all<br />

these factors mesh together requires historical data and data analysis. A lot of it.<br />

These are complex and critical problems we’re trying to solve. And cloud and machine learning technology is<br />

helping us push boundaries of what is possible in ways I couldn’t have imagined a few years ago. — Azizan Aziz,<br />

Senior Research Architect<br />

THE DATA CHALLENGE MEETS THE DATA SLEUTHS<br />

Making all the captured data from buildings work together is like putting together a massive jigsaw puzzle. Some<br />

buildings on campus, such as the Gates Center, have hundreds of sensors, and others not so many. These sensors<br />

are tracking CO2 levels in different rooms, measuring the distribution of temperatures by floor, by room and by<br />

height, monitoring windows, lighting systems and plug loads. And there’s more: People who work inside make up<br />

the most significant part of a building’s heartbeat — so user satisfaction data is being added to the mix based on<br />

occupant surveys in order to have a holistic picture of the indoor environmental quality of the workplace.<br />

To say it’s a complex task would be putting it lightly. Lasternas and Aziz spend a good deal of time being data<br />

sleuths, and finding ways to listen to what the buildings are trying to communicate — the story that lives in the data.<br />

There is a real difference you can make in energy conservation by giving people data that is actionable instead of<br />

asking them to just do their best — Bertrand Lasternas, Senior Researcher<br />

When Lasternas came to Carnegie Mellon from France in 2010, he was a physics and chemistry major working<br />

towards a master’s degree in mechanical engineering and building sciences. Today, he’s an expert in extracting<br />

data from building management systems and sensors, both to understand how buildings work, as well as to help<br />

people manage energy more efficiently.<br />

Recalling challenges from the earlier phases of the research, Lasternas says, “We might have 10 different manufacturers<br />

of equipment in a single building, and none of them share information. So how do you pull all of that<br />

together? We wanted to empower people to be more engaged in the living building, more aware of their energy<br />

usage patterns.”<br />

With help from Microsoft’s Global ISV partner OSIsoft, Lasternas and Aziz began using their solution, the PI System,<br />

four years ago. It offered the missing “glue” that helped the team bring data together from various sources,<br />

“cleanse” it, store it in a common, usable format, and make it ready for historical and real-time analysis. The PI<br />

System supports more than 400 interfaces that can connect to systems from the many different vendors of building<br />

systems and controls.<br />

THE MACHINE LEARNING BREAKTHROUGH<br />

“We’re not trained data scientists. We went overnight from using complex statistical analysis tools to drag-n-drop<br />

insights. That’s a breakthrough for the work we do” — Senior Researcher Azizan Aziz<br />

Having conquered the data integration and storage challenge, the team dove into analysis — a world of massive<br />

spreadsheets and programming languages such as MATLAB to handle big, iterative computations. It was an<br />

exercise that very quickly got unwieldy. “We’re not trained data scientists by background, and complex statistical<br />

packages are outside of our immediate area of expertise,” says Aziz.<br />

“One of our former students was using MATLAB for analysis,” he recalls. “It took her a long time just to prepare and<br />

sort the data, and then a single run of analysis took 30-45 minutes. That’s far too long to develop good predictions<br />

for demand reduction. We really need to do these iterative analyses in real-time.”<br />

Machine Learning, cloud and data visualization technologies changed the dynamics of their project dramatically.<br />

“With Azure Machine Learning, the time it took to run a single experiment went from 45 minutes to instantaneous,”<br />

Aziz says. “It’s really fun to be able to use multiple types of machine learning algorithms and just have the results<br />

appear immediately. We’re able to play with all the variables and make sense of which ones contribute most to a<br />

specific change in building conditions.”<br />

LETTING THE DATA TELL THE STORY<br />

To let the data tell its own story in a way that is visual and easy to grasp, the Carnegie Mellon researchers build<br />

“digital dashboards” that make data anomalies much easier to spot. Using these dashboards, they’ve been able to<br />

solve puzzles in the buildings they’re working on. In one case, Lasternas recalls, “We saw an unusual area of low<br />

temperature in a building and realized that someone was leaving a window open in the middle of winter, when it<br />

was minus-eight degrees outside.”<br />

According to Aziz, when a strange condition is spotted on the dashboard, the solution is often a simple one. “We<br />

ask people why they have the boiler on when the temperature outside is 85 degrees. Turns out they didn’t know it<br />

was on, because they don’t have the data presented to them clearly,” he says.<br />

Having data-based insight on-the-fly is great, but where things get really interesting is with the potential to do predictive<br />

modeling. This is an area where cloud and machine learning technologies have truly been a game changer.<br />

Because Carnegie Mellon is collecting and storing real-time and historical data on campus buildings using the PI<br />

System, they finally have the ability to do predictive analysis using Azure Machine Learning in exciting ways.<br />

For people who live in buildings and use its systems, providing data alone isn’t enough to change behavior. “People<br />

need to see the impact of their actions every minute. Digital dashboards often trigger the “aha!” moments.”<br />

— Lasternas<br />

One of the team’s early experiments involved trying to figure out the ideal time to ramp up the heating in campus<br />

buildings to hit 72 degrees at start of business (by 8 a.m.), given predicted variations in outdoor temperature and<br />

sunshine. Using Azure Machine Learning, they built a model that looked at months of “heat up” data from the building’s<br />

records and matched that to multi-day external temperatures and anticipated solar radiation. The result? They<br />

were able to zero in on a custom model for each day to start heating a building at the lowest energy use.<br />

“As simple as that victory sounds, the implications for energy and dollar savings are simply enormous —especially<br />

when you scale up,” notes Lasternas. For this group of researchers, the potential to scale up such predictive ca-<br />

Document réalisé par la Société Corp Events - Janvier 2015<br />

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