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Design of Rate-Compatible Protograph LDPC Codes

This method can be applied in wireless cellular, satellite, and Internet communications. NASA’s Jet Propulsion Laboratory, Pasadena, California The most common way to generate a rate-compatible family of codes is puncturing. In this method, one starts with a low-rate mother code and then selectively discards some of the coded bits to arrive at higher-rate codes. This approach is simple, but is not free of problems. Specifically, the mother code is optimally designed for low rates, so higher-rate punctured codes have a wider gap to capacity, and the optimal low-rate code structure and puncturing patterns are designed separately, which is suboptimal. Even though it has been shown that puncturing can theoretically achieve the same gap to capacity as the mother code, in existing codes puncturing has in creased the gap significantly.

Posted in: Information Sciences, Electronics & Computers, Briefs

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Model Predictive Automatic Recovery System

This innovation is designed for aircraft on the verge of a loss-of-control situation. John H. Glenn Research Center, Cleveland, Ohio In commercial aviation, there have been several recent cases of unstabilized approaches that have resulted in crash landings short of the runway. Some of the direst consequences of these incidents may be prevented with the addition of a level of autonomy — a supervisory envelope protection scheme that anticipates loss-of-control accidents and intercedes to prevent them.

Posted in: Information Sciences, Electronics & Computers, Briefs

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Rapid Prototyping Lab (RPL) Generic Display Engine

Lyndon B. Johnson Space Center, Houston, Texas Spacecraft display software is very costly and requires extensive testing and certification. Much testing must be repeated if the display software is changed in any way. Additionally, hand-coded displays are costly to create and maintain. For certain types of display formats with limited graphical content, the hand-coding is very repetitive between display formats.

Posted in: Information Sciences, Electronics & Computers, Briefs

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Product of the Month: October 2014

National Instruments, Austin, TX, has introduced the NI VirtualBench that combines five instruments in one device: a mixed-signal oscilloscope, a digital multimeter, a function generator, a programmable DC power supply, and digital I/O. The software-based device integrates with PCs and iPads, and offers WiFi and USB connectivity. It measures 10 × 7.5 × 2.9" and is portable with an optional carrying case. User interfaces for each instrument are consolidated into one for viewing and interacting with all instruments at once. A mouse and scroll wheel can be used on a PC, or pinch and zoom on an iPad with finger touch. Users can instantly document results by clicking or tapping a button to save screenshots and data to an iPad or PC. When plugged into a USB port, VirtualBench software automatically loads on PCs with Windows AutoPlay. The device integrates with NI LabVIEW software for building custom applications to programmatically control VirtualBench.

Posted in: Electronics & Computers, Products

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NASA’s Space Station Fix-It for Satellites

NASA’s fix-it investigation on the International Space Station (ISS), the Robotic Refueling Mission (RRM), has moved one step closer to its 2.0 update with the delivery of new RRM hardware. The RRM module, affixed to an exterior ISS platform since 2011, now awaits the robotic transfer of two new task boards and a borescope inspection tool that will equip RRM for a new round of satellite-servicing demonstrations.

Posted in: UpFront

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The Power of Salt

Where the river meets the sea, there is the potential to harness a significant amount of renewable energy, according to mechanical engineers at MIT. They evaluated an emerging method of power generation called pressure retarded osmosis (PRO) in which two streams of different salinity are mixed to produce energy. In principle, a PRO system would take in river water and seawater on either side of a semi-permeable membrane. Through osmosis, water from the less-salty stream would cross the membrane to a pre-pressurized saltier side, creating a flow that can be sent through a turbine to recover power.

Posted in: UpFront

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A New Paradigm for Mid-Lifecycle Design Changes

For decades, replacing key components during the mid-lifecycle design refresh was seen as simply too costly and burdensome. Changes had to wait until the next generation. Today, technology changes too fast to wait to add new capabilities. Fortunately, there are other options. With the right partners and suppliers involved, a mid-lifecycle component change can provide cost savings and greater performance capabilities. This white paper explores when and why a mid-lifecycle component change makes sense.

Posted in: Electronics & Computers, White Papers

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