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Counting People With WiFi

Researchers in UC Santa Barbara professor Yasamin Mostofi’s lab are proving that wireless signals can do more than provide Internet access. They have demonstrated that a WiFi signal can be used to count the number of people in a given space, leading to diverse applications, from energy efficiency to search-and-rescue.


 

“Our approach can estimate the number of people walking in an area, based on only the received power measurements of a WiFi link,” said Mostofi,  a professor of electrical and computer engineering. This approach does not require people to carry WiFi-enabled telecommunications devices for them to be counted, Mostofi emphasized.

 

To accomplish this feat of people-counting, the researchers put two WiFi cards at opposite ends of a target area, a roughly 70-square-meter space. Using only the received power measurements of the link between the two cards, their approach can estimate the number of people walking in that area. So far, they have successfully tested with up to and including nine people in both indoor and outdoor settings. The findings of Mostofi’s research group are scheduled for publication in the Institute of Electrical and Electronics Engineers Journal on Selected Areas in Communications’ special issue on location-awareness for radios and networks.

 

“This is about counting walking people, which is very challenging,” said Mostofi. “Counting this many people in such a small area with only WiFi power measurements of one link is a hard problem, and the main motivation for this work.”

 

This people-counting method relies in large part on the changes of the received wireless signal, according to the researchers. The presence of people attenuates the signal in the direct line of sight between the WiFi cards if a person crosses the line of sight, and human bodies also scatter the signal — resulting in a phenomenon called multi-path fading — when they are not in the direct line of sight path. By developing a probabilistic mathematical framework based on these two key phenomena, the researchers have then proposed a way of estimating the number of people walking in the space.

 

With the near-ubiquity of WiFi in many settings, the researchers’ findings have the potential for many diverse applications. For instance, the ability to estimate the number of people in a given space could be used in smart homes and buildings, so air conditioning and heating could be adjusted according to the level of occupancy. “Stores can benefit from counting the number of shoppers for better business planning,” noted Mostofi.

 

Security and search-and-rescue operations could also take advantage of occupancy estimation. Previous work in the research lab involved imaging stationary objects/humans through walls with WiFi signals, and Mostofi plans to eventually bring the two projects together in the future.

 

 

 

 

Source:- University of California – Santa Barbara.

 

 

Published on 15th June 2015

Satellites peer into rock 50 miles beneath Tibetan Plateau

Gravity data captured by satellite has allowed researchers to take a closer look at the geology deep beneath the Tibetan Plateau.

 

The analysis, published in the journal Nature Scientific Reports, offers some of the clearest views ever obtained of rock moving up to 50 miles below the plateau, in the lowest layer of Earth’s crust.


There, the Indian tectonic plate presses continually northward into the Eurasian tectonic plate, giving rise to the highest mountains on Earth—and deadly earthquakes, such as the one that killed more than 9,000 people in Nepal earlier this year.

 

The study supports what researchers have long suspected: Horizontal compression between the two continental plates is the dominant driver of geophysical processes in the region, said C.K. Shum, professor and Distinguished University Scholar in the Division of Geodetic Science, School of Earth Sciences at The Ohio State University and a co-author of the study.

 

 

“The new gravity data onboard the joint NASA-German Aerospace Center GRACE gravimeter mission and the European Space Agency’s GOCE gravity gradiometer missionenabled scientists to build global gravity field models with unprecedented accuracy and resolution, which improved our understanding of the crustal structure,” Shum said. “Specifically, we’re now able to better quantify the thickening and buckling of the crust beneath the Tibetan Plateau.”

 

 

 

Shum is part of an international research team led by Younghong Shin of the Korea Institute of Geosciences and Mineral Resource. With other researchers in Korea, Italy and China, they are working together to conduct geophysical interpretations of the Tibetan Plateau geodynamics using the latest combined gravity measurements by the GOCE gravity gradiometer and the GRACE gravimeter missions.

 

Satellites such as GRACE and GOCE measure small changes in the force of gravity around the planet. Gravity varies slightly from place to place in part because of an uneven distribution of rock in Earth’s interior.

 

The resulting computer model offers a 3-D reconstruction of what’s happening deep within the earth.

 

As the two continental plates press together horizontally, the crust piles up. Like traffic backing up on a congested freeway system, the rock follows whatever side roads may be available to relieve the pressure.

 

But unlike cars on a freeway, the rock beneath Tibet has two additional options for escape. It can push upward to form the Himalayan mountain chain, or downward to form the base of the Tibetan Plateau.

 

The process takes millions of years, but caught in the 3-D image of the computer model, the up-and-down and side-to-side motions create a complex interplay of wavy patterns at the boundary between the crust and the mantle, known to researchers as the Mohorovičić discontinuity, or “Moho.”

 

“What’s particularly useful about the new gravity model is that it reveals the Moho topography is not random, but rather has a semi-regular pattern of ranges and folds, and agrees with the ongoing tectonic collision and current crustal movement measured by GPS,” Shin said.

 

As such, the researchers hope that the model will provide new insights into the analysis of collisional boundaries around the world.

 

Co-author Carla Braitenberg of the University of Trieste said that the study has already helped explain one curious aspect of the region’s geology: the sideways motion of the Tibetan Plateau. While India is pushing the plateau northward, GPS measurements show that portions of the crust are flowing eastward and even turning to the southeast.

 

“The GOCE data show that the movement recorded at the surface has a deep counterpart at the base of the crust,” Braitenberg said. Connecting the rock flow below to movement above will help researchers better understand the forces at work in the region.

 

Those same forces led to the deadly Nepal earthquake in April 2015. But Shum said that the new model almost certainly won’t help with earthquake forecasting—at least not in the near future.

 

“I would say that we would understand the mechanism more if we had more measurements,” he said, but such capabilities “would be very far away.”

 

Even in California—where, Shum pointed out, different tectonic processes are at work than in Tibet—researchers are unable to forecast earthquakes, despite having abundant GPS, seismic and gravity data. Even less is known about Tibet, in part because the rough terrain makes installing GPS equipment difficult.

 

Other co-authors on the study included Sang Mook Lee of Seoul National University; Sung-Ho Na of the University of Science and Technology in Daejeon, Korea;

 

Kwang Sun Choi of Pusan National University; Houtse Hsu of the Institute of Geodesy & Geophysics, Chinese Academy of Sciences; and Young-Sue Park and Mutaek Lim of the Korea Institute of Geosciences and Mineral Resource.

 

 

 

 

This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources, funded by the Ministry of Science, ICT and Future Planning of Korea. Shum was partially supported by NASA’s GRACE Science Team Program and Concept in Advanced Geodesy Program. Braitenberg was partially supported by the European Space Agency’s Center for Earth Observation as part of the GOCE User ToolBox project.

 

 

 

 

Source: University of Illinois at Chicago

 

 

Published on   24th July 2015

Predicting Tree Mortality

A combination of drought, heat and insects is responsible for the death of more than 12 million trees in California, according to a new study from UC Santa Barbara’s National Center for Ecological Analysis and Synthesis (NCEAS). Members of the NCEAS working group studying environmental factors contributing to tree mortality expect this number to increase with climate change.


 

Forest die-off Colorado

 

The western U.S. has been a hotspot for forest die-offs such as this one in Colorado.

 

Credit: Courtesy of William M. Ciesla, Forest Health Management

 

The study is the first of its kind to examine the wide spectrum of interactions between drought and insects. Lead author William Anderegg, a postdoctoral researcher at the Princeton Environmental Institute, and his coauthors first devised a framework to look at the effects that each stressor can have on tree mortality and then examined interactions among them. The researchers’ findings appear in New Phytologist.

 

“We wanted to be able to get a sense of how these die-off patterns will shift with climate change,” explained study coauthor Naomi Tague, an associate professor at UCSB’s Bren School of Environmental Science & Management. “Are there huge forests that will be at higher risk of dying sooner?”

 

The western U.S. has been a hotspot for forest die-offs. Local economies in states like California and Colorado are highly dependent on the nature-based tourism and recreation provided by forests, which offer a scenic backdrop to the skiing, fishing and backpacking opportunities that draw so many people to live and play in the West. But lingering drought, rising temperatures and outbreaks of tree-killing pests such as bark beetles have spurred an increase in widespread tree mortality — especially within the past decade.

 

“Very often both drought and insects together are responsible for tree mortality,” explained Anderegg, “but there are several good examples of trees dying because of one impact and not the other. We’ve worked to detail the spectrum of interactions between drought and insects and examine how they go hand in hand to affect tree die-offs.”

 

Forest mortality has also been shown to impact everything from real estate to clean water. Property values in Colorado plummeted after swaths of coniferous forests were damaged by pine beetle infestations. Water purification services provided by forests continue to be disrupted when hectares of forests are lost to pests and drought. What’s more, forest die-off events are projected to increase in frequency and severity in the coming decades.

 

“If we want to account for forest die-off events at local and global scales, we need some way of estimating how often they are likely to occur,” Tague said. “We’re putting together the pieces of how climate conditions can affect that mortality and how to identify the specific stressors that cause it.”

 

The study’s framework is a first step toward developing the tools that resource managers need to better predict the impacts of climate change on forests. Scientists and forest specialists are now tasked not only with determining what conditions prompt tree mortality but also how they will shape forested landscapes in the years to come. Being able to predict forest mortality in a changing climate is key to conservation and land use planning.

 

“Ultimately, forests are a critical part of western U.S. landscapes and state economies,” Anderegg said. “They are also a canary in the coal mine for climate change. These massive forest die-offs that we are starting to see are a sign that climate change is already having major impacts in our backyard.”

 

 

 

Source:- University of California – Santa Barbara.

 

 

Published on 15th June 2015

Sex and violence may not really sell products

If there’s one thing advertisers think they know, it is that sex and violence sell.


A new analysis, however, provides some of the best evidence to date that this widely accepted adage just isn’t true.

 

Researchers analyzed the results of 53 different experiments (a so-called meta-analysis) involving nearly 8,500 people, done over 44 years. All of these experiments examined some facet of the question of whether sexual or violent media content could help sell advertised products.

 

When all the results are considered together, the overall conclusion, with some caveats, is that programs featuring violence and sex aren’t the ideal context for effective advertising, said Brad Bushman, co-author of the study and professor of communication and psychology at The Ohio State University.

 

It’s not that people don’t pay attention to sex and violence in the media, Bushman said. In fact, an evolutionary perspective would say it is just the opposite.

 

“People are so focused on the sex and violence they see in the media that they pay less attention to the advertising messages that appear along with it,” Bushman said.

 

“Advertisers shouldn’t be so sure that sex and violence can help them sell their products.”

 

 

Bushman conducted the study with Robert Lull, who just earned his Ph.D. in communication at Ohio State. The results were published online yesterday in the journal Psychological Bulletin and will be featured in a future print edition.

 

Their analysis included studies involving a variety of types of media, including print, TV, movies and even a few video games. They examined studies in which the ads themselves contained sex or violence and studies in which only the media surrounding the ads contained such content.

 

In all cases, the researchers had studied whether sex and violence affected brand memory, brand attitudes and people’s intention to buy the products advertised.

 

 

They found that memory for brands and ads was significantly impaired in programs containing sex, violence, or both sex and violence.

 

Overall, people had less favorable attitudes toward brands that advertised in violent media compared to neutral media. Only one study examined attitudes toward brands in sexual media and that pointed toward less favorable attitudes as well.

 

And people reported less intention to buy brands that were advertised in media containing violence, sex or both, compared to the same brands in media containing no sex or violence.

 

But what about ads that themselves featured sex and violence? Here, the findings were not as clear-cut. Overall, memory for brands that featured sex and violence was not impaired.

 

But attitudes toward brands that featured sexual ads were significantly lower than those same brands in neutral ads. Only one study examined attitudes toward brands in violent ads and those results also trended toward less favorable attitudes.

 

Overall, buying intentions did not depend on whether the ad contained sex or violence.

 

While these overall conclusions were clear, Lull and Bushman found several nuances in the studies they examined.

 

Memory for ads and buying intentions were both improved when the ad content and the media content were matching in terms of sex and violence. For example, violent ads worked best when they were paired with violent programs, Lull said.

 

“If a TV program prompts violent or sexual thoughts, an ad that prompts similar thoughts will be better remembered,” Lull said.

 

Sexual ads didn’t hurt brand attitudes and buying intentions overall. But the higher the levels of sexual content in the ads, the more negative the attitude people had toward the brand and the less likely they were to say they would buy the product.

 

Older people in the studies were less likely to say they would buy products featured in violent or sexual ads, compared to younger people.

 

Men’s brand memory was more impaired than women’s when watching media content or ads featuring sexual or violent imagery.

 

“This fits in with evolutionary theory that suggests males pay more attention to violence and sex than women do,” Lull said. “Because they’re paying more attention to this content, they are less likely to remember the ads.”

 

Another interesting finding was that memory impairments and negative attitudes toward brands featured in violent or sexual ads have actually decreased over the past decades.

 

This study can’t say for sure, but one explanation is that people have started to become desensitized to sex and violence in ads, Bushman said

 

“Viewers are so accustomed to seeing violent and sexual media content that they don’t respond as much today to the attention-grabbing impact as they did in previous decades,” he said.

 

Bushman said he is continuing work in his laboratory to examine the effects of violent ads on memory.

 

 

 

 

Source: University of Illinois at Chicago

 

 

Published on   24th July 2015

What is Lewy Body Dementia, Which Robbed Robin Williams of His Sanity?

Oscar-winning actor and comedian Robin Williams died in August 2014 of suicide. His death was not due to substance abuse or suicidal tendencies, as some had speculated in the media. Williams’ wife, Susan, told ABC’s “Good Morning America” this month that her husband slowly lost his mind because of a neurological disease, later discovered in an autopsy to be Lewy body dementia.
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