Tech Briefs

Universal Sparse Modeling

Sparse data models, where data is assumed to be well represented as a linear combination of a few elements from a dictionary, have gained considerable attention in recent years, and their use has led to state-of-the-art results in many signal and image processing tasks. Sparse modeling calls for constructing a succinct representation of some data as a combination of a few typical patterns (atoms) learned from the data itself.

Posted in: Briefs, Information Technology, Mathematical models, Data management, Terminology

Web Service and Interface for Remote Electronic Device Characterization

A lightweight Web Service (WS) and a Web site interface have been developed that enable remote measurements of electronic devices as a “virtual laboratory.” Using standard browsers without additional plug-ins (such as Internet Explorer, Firefox, or even Safari on an iPhone), remote users can control a Keithley Instruments’ source-measurement unit and monitor results in real time from anywhere on the Internet. The present interface is flexible, and could be expanded to many other devices and instruments, such as remote measurements of bionanotechnology or micromechanical devices.

Posted in: Briefs, Information Technology, Measurements, Computer software / hardware, Internet, Human machine interface (HMI), Test equipment and instrumentation

Comparison of Subpixel Phase Correlation Methods for Image Registration

When working sequences of images, registration of the frames to a common point of reference is an essential prerequisite for many types of image analysis. The phase correlation method (PCM) is a popular Fourier domain method to register two images. It computes a phase difference map that (ideally) contains a single peak. The location of the peak is proportional to the relative translation [dx, dy] between the two images. The PCM is resilient to noise and image defects and is readily automated.

Posted in: Briefs, Information Technology, Analysis methodologies, Imaging, Satellites

High-Temperature Silicon Carbide Power Module for Military Hybrid Electric Vehicles

The ever-increasing electrical power, power density, and cooling requirements of present and future military platforms are pushing silicon-based power electronics systems to their operational limits. To address future needs, wide bandgap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) were developed for electronic applications. Using these semiconductor materials, a new generation of wide bandgap power devices is being developed.

Posted in: Briefs, Materials, Power electronics, Materials properties, Semiconductors, Hybrid electric vehicles, Military vehicles and equipment

Prognostic Health Management for Avionics System Power Supplies

Electronic systems such as electronic controls, onboard computers, communications, navigation, and radar perform many critical functions onboard military and commercial aircraft. All of these systems depend on electrical power supplies for direct current (DC) power at a constant (regulated) voltage to drive solid-state electronics. With these power supplies playing an important role in the operation of aircraft systems and subsystems, flight and ground crews need health state awareness and prediction tools that diagnose faults accurately, predict failures, and project life remaining of these components.

Posted in: Briefs, Electronics & Computers, Avionics, Electronic equipment, Electric power, Prognostics, Commercial aircraft, Military aircraft

Energy-Scalable Protocols for Battery Operated Micro Sensor Networks

Networks of microsensors can greatly improve environment monitoring for many civil and military applications. Multiple sensors provide fault tolerance and can provide valuable inferences about the physical world to the end user. In order to prolong the lifetimes of wireless sensors, all aspects of a sensor system should be energy efficient. To maximize battery lifetimes of distributed wireless sensors, network protocols and data fusion algorithms should be designed with low-power techniques. Network protocols minimize energy by using localized communication and control and by exploiting computation/communication tradeoffs. A sensor network system that uses a localized clustering protocol and beamforming data fusion was developed to enable energy-efficient collaboration.

Posted in: Briefs, Electronics & Computers, Mathematical models, Architecture, Sensors and actuators, Surveillance, Energy consumption

Fabrication of Carbon Nanotube Channels on Three- Dimensional Building Blocks

Single-wall carbon nanotubes (SWNTs) are the most attractive material in the fields of nanoscience and nanotechnology due to their chemical, physical, and electrical properties. Carbon nanotubes (CNTs) are being applied in various kinds of nano devices such as transistors, electrodes, sensors, and filters because of the semiconducting, metallic, optical, and structural properties. To date, CNTs are mainly synthesized, grown, and dispersed on a two-dimensional substrate. However, it is not easy to fabricate and manipulate CNTs on a particularly structured substrate for various applications. In the case of CNTs on planar substrates, it is hard to get high conductivity and sensitivity because of physical disconnection and low surface areas due to randomly oriented two-dimensional structure.

Posted in: Briefs, Manufacturing & Prototyping, Fabrication, Nanomaterials, Nanotechnology