Atif Shamim and Christian Claudel, KAUST Assistant Professors of Electrical Engineering, work together on creating wireless sensor networks for “smart cities.” Prof. Shamim describes it as “game changing…It will change the way we do many things in our lives, moving us towards smarter living.”
In the “smart cities” of the future, electronic devices and objects will be “smart,” with objects containing sensors that communicate with each other, fixed network nodes and central servers. These sensors are connected through the Internet of things (IOT), which enables them to share information. Intelligent systems at the central servers are then used to analyze and process the data from the sensors.
“The critical component for these processes is low-cost wireless sensing modules,” explained Prof. Shamim. “Fixed sensor nodes are useful, but for these you need a lot of infrastructure, such as towers and assemblies. Our idea is that you would have some fixed sensors, but you would disperse many small, mobile sensors that communicate wirelessly to the fixed sensors, which then communicate all the received information to a central station for analysis.”
The use of small, mobile sensors reduces the cost of the infrastructure tremendously, noted Prof. Shamim, and also enables information to be gathered from remote locations where it is difficult or impossible to mount fixed sensors, such as in forests or deserts.
Together, the research groups of Prof. Shamim and Prof. Claudel combined their respective talents and expertise to make progress in using wireless sensors for flood monitoring. This issue is of high importance to Saudi Arabia and cities such as Jeddah, which saw a 2009 catastrophic flood claim the lives of hundreds and cause considerable property damage.
“Classical sensing solutions, such as fixed wireless sensor networks or satellite imagery, are too expensive or too inaccurate to detect floods – and in particular flash floods – well,” noted Prof. Claudel. “Instead, we tested the use of Unmanned Aerial Vehicles (UAVs) equipped with mobile, floatable, 3D printed microsensors and sensor delivery systems to sense and monitor flash flooding events.”
This new system of mobile, floatable sensing, called Lagrangian sensing, “is very promising for large scale sensing, or on-demand sensing, as it requires minimal infrastructure,” the researchers stated. Using this method, UAVs drop the small, disposable wireless sensors over an area to be monitored. The sensors float, so they are carried away by the water flow of the flood. As they move along in the water, they send signals to the UAVs. These signals map the extent of the flood, and this information is transmitted to a central, fixed station for processing. It can then be used to warn the public and other authorities about the extent of the flood.
“Prof. Claudel carries out the systems level design and implementation for the research project, and my group develops the actual physical sensors,” said Prof. Shamim. “In that way, I believe we are a very good fit for collaboration.”
Article source: http://www.pcb007.com/pages/zone.cgi?a=104408
Lasers – devices that deliver beams of highly organized light – are so deeply integrated into modern technology that their basic operations would seem well understood. CD players, medical diagnostics and military surveillance all depend on lasers.
Re-examining longstanding beliefs about the physics of these devices, Princeton engineers have now shown that carefully restricting the delivery of power to certain areas within a laser could boost its output by many orders of magnitude. The finding, published Oct. 26 in the journal Nature Photonics, could allow far more sensitive and energy-efficient lasers, as well as potentially more control over the frequencies and spatial pattern of light emission.
“It’s as though you are using loss to your advantage,” said graduate student Omer Malik, an author of the study along with Li Ge, now an assistant professor at the City University of New York, and Hakan Tureci, assistant professor of electrical engineering at Princeton. The researchers said that restricting the delivery of power causes much of the physical space within a laser to absorb rather than produce light. In exchange, however, the optimally efficient portion of the laser is freed from competition with less efficient portions and shines forth far more brightly than previous estimates had suggested.
The results, based on mathematical calculations and computer simulations, still need to be verified in experiments with actual lasers, but the researchers said it represents a new understanding of the fundamental processes that govern how lasers produce light.
“Distributing gain and loss within the material is a higher level of design – a new tool – that had not been used very systematically until now,” Tureci said.
The heart of a laser is a material that emits light when energy is supplied to it. When a low level of energy is added, the light is “incoherent,” essentially meaning that it contains a mix of wavelengths (or colors). As more energy is added, the material suddenly reaches a “lasing” threshold when it emits coherent light of a particular wavelength.
The entire surface of the material does not emit laser light; rather, if the material is arranged as a disc, for example, the light might come from a ring close to the edge. As even more energy is added, more patterns emerge – for example a ring closer to the center might reach the laser threshold. These patterns – called modes – begin to interact and sap energy from each other. Because of this competition, subsequent modes requiring higher energy may never reach their lasing thresholds. However, Tureci’s research group found that some of these higher threshold modes were potentially far more efficient than the earlier ones if they could just be allowed to function without competition.
Article source: http://www.pcb007.com/pages/zone.cgi?a=104414
Apple has announced financial results for its fiscal 2014 fourth quarter ended September 27, 2014. The company posted quarterly revenue of $42.1 billion and quarterly net profit of $8.5 billion, or $1.42 per diluted share. These results compare to revenue of $37.5 billion and net profit of $7.5 billion, or $1.18 per diluted share, in the year-ago quarter. Gross margin was 38% compared to 37% in the year-ago quarter. International sales accounted for 60% of the quarter’s revenue.
Apple’s board of directors has declared a cash dividend of $.47 per share of the company’s common stock. The dividend is payable on November 13, 2014, to shareholders of record as of the close of business on November 10, 2014.
“Our fiscal 2014 was one for the record books, including the biggest iPhone launch ever with iPhone 6 and iPhone 6 Plus,” said Tim Cook, CEO. “With amazing innovations in our new iPhones, iPads and Macs, as well as iOS 8 and OS X Yosemite, we are heading into the holidays with Apple’s strongest product lineup ever. We are also incredibly excited about Apple Watch and other great products and services in the pipeline for 2015.”
“Our strong business performance drove EPS growth of 20 percent and a record $13.3 billion in cash flow from operations in the September quarter,” said Luca Maestri, CFO. “We continued to execute aggressively against our capital return program, spending over $20 billion in the quarter and bringing cumulative returns to $94 billion.”
Apple is providing the following guidance for its fiscal 2015 first quarter:
- Revenue between $63.5 billion and $66.5 billion;
- Gross margin between 37.5% and 38.5%;
- Operating expenses between $5.4 billion and $5.5 billion;
- Other income/(expense) of $325 million; and
- Tax rate of 26.5%.
Apple designs Macs, the best personal computers in the world, along with OS X, iLife, iWork, and professional software. Apple leads the digital music revolution with its iPods and iTunes online store. Apple has reinvented the mobile phone with its revolutionary iPhone and App Store, and is defining the future of mobile media and computing devices with iPad.
Article source: http://www.pcb007.com/pages/zone.cgi?a=104229