257 research outputs found
Optical transparency of graphene as determined by the fine-structure constant
The observed 97.7% optical transparency of graphene has been linked to the
value 1/137 of the fine structure constant, by using results for noninteracting
Dirac fermions. The agreement in three significant figures requires an
explanation for the apparent unimportance of the Coulomb interaction. Using
arguments based on Ward identities, the leading corrections to the optical
conductivity due to the Coulomb interactions are correctly computed (resolving
a subtle theoretical issue) and shown to amount to only 1-2%, corresponding to
0.03-0.04% in the transparency.Comment: 5 pages, 2 figures, Minor changes, published version with a new titl
Experimenting with an Evolving Ground/Space-based Software Architecture to Enable Sensor Webs
A series of ongoing experiments are being conducted at the NASA Goddard Space Flight Center to explore integrated ground and space-based software architectures enabling sensor webs. A sensor web, as defined by Steve Talabac at NASA Goddard Space Flight Center(GSFC), is a coherent set of distributed nodes interconnected by a communications fabric, that collectively behave as a single, dynamically adaptive, observing system. The nodes can be comprised of satellites, ground instruments, computing nodes etc. Sensor web capability requires autonomous management of constellation resources. This becomes progressively more important as more and more satellites share resource, such as communication channels and ground station,s while automatically coordinating their activities. There have been five ongoing activities which include an effort to standardize a set of middleware. This paper will describe one set of activities using the Earth Observing 1 satellite, which used a variety of ground and flight software along with other satellites and ground sensors to prototype a sensor web. This activity allowed us to explore where the difficulties that occur in the assembly of sensor webs given today s technology. We will present an overview of the software system architecture, some key experiments and lessons learned to facilitate better sensor webs in the future
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App Store for EHRs and Patients Both
The Substitutable Medical Applications, Reusable Technologies (SMART) Platforms project ( www.smartplatforms.org ) seeks to develop an iPhone-like health information technology platform with substitutable apps constructed around core services. It is funded by a grant from the Office of the National Coordinator of Health Information Technology’s Strategic Health IT Advanced Research Projects (SHARP) Program. SMART technologies enable existing electronic health records and HIT platforms to run substitutable apps. Substitutability is the capability inherent in a system of replacing one application with another of similar functionality. We created a patient-facing SMART instance using the open source Indivo personally controlled health record (PCHR). The SMART “read-only” API has been deployed on multiple systems, including the Cerner installation at Boston Children’s Hospital and the World Vista EHR. We sought to SMART-enable Indivo, the open source reference PCHR upon which HealthVault and other PCHRs were modeled. PCHRs provide patients with a secure repository of their health information that can be exposed to apps across a programming interface. We updated the open source Indivo PCHR to support the SMART API, enabling Indivo to act as a patient-facing apps platform, running the same or similar versions of apps that face clinicians
Matsu: An Elastic Cloud Connected to a SensorWeb for Disaster Response
This slide presentation reviews the use of cloud computing combined with the SensorWeb in aiding disaster response planning. Included is an overview of the architecture of the SensorWeb, and overviews of the phase 1 of the EO-1 system and the steps to improve it to transform it to an On-demand product cloud as part of the Open Cloud Consortium (OCC). The effectiveness of this system is demonstrated in the SensorWeb for the Namibia flood in 2010, using information blended from MODIS, TRMM, River Gauge data, and the Google Earth version of Namibia the system enabled river surge predictions and could enable planning for future disaster responses
HyspIRI Intelligent Payload Module(IPM) and Benchmarking Algorithms for Upload
Features: Hardware: a) Xilinx Virtex-5 (GSFC Space Cube 2); b) 2 x 400MHz PPC; c) 100MHz Bus; d) 2 x 512MB SDRAM; e) Dual Gigabit Ethernet. Support Linux kernel 2.6.31 (gcc version 4.2.2). Support software running in stand alone mode for better performance. Can stream raw data up to 800 Mbps. Ready for operations. Software Application Examples: Band-stripping Algiotrhmsl:cloud, sulfur, flood, thermal, SWIL, NDVI, NDWI, SIWI, oil spills, algae blooms, etc. Corrections: geometric, radiometric, atmospheric. Core Flight System/dynamic software bus. CCSDS File Delivery Protocol. Delay Tolerant Network. CASPER /onboard planning. Fault monitoring/recovery software. S/C command and telemetry software. Data compression. Sensor Web for Autonomous Mission Operations
Re-engineering the mission life cycle with ABC and IDEF
The theory behind re-engineering a business process is to remove the non-value added activities thereby lowering the process cost. In order to achieve this, one must be able to identify where the non-value added elements are located which is not a trivial task. This is because the non-value added elements are often hidden in the form of overhead and/or pooled resources. In order to be able to isolate these non-value added processes from among the other processes, one must first decompose the overall top level process into lower layers of sub-processes. In addition, costing data must be assigned to each sub-process along with the value the sub-process adds towards the final product. IDEF0 is a Federal Information Processing Standard (FIPS) process-modeling tool that allows for this functional decomposition through structured analysis. In addition, it illustrates the relationship of the process and the value added to the product or service. The value added portion is further defined in IDEF1X which is an entity relationship diagramming tool. The entity relationship model is the blueprint of the product as it moves along the 'assembly line' and therefore relates all of the parts to each other and the final product. It also relates the parts to the tools that produce the product and all of the paper work that is used in their acquisition. The use of IDEF therefore facilitates the use of Activity Based Costing (ABC). ABC is an essential method in a high variety, product-customizing environment, to facilitate rapid response to externally caused change. This paper describes the work being done in the Mission Operations Division to re-engineer the development and operation life cycle of Mission Operations Centers using these tools
On Reducing the Amount of Samples Required for Training of QNNs: Constraints on the Linear Structure of the Training Data
Training classical neural networks generally requires a large number of
training samples. Using entangled training samples, Quantum Neural Networks
(QNNs) have the potential to significantly reduce the amount of training
samples required in the training process. However, to minimize the number of
incorrect predictions made by the resulting QNN, it is essential that the
structure of the training samples meets certain requirements. On the one hand,
the exact degree of entanglement must be fixed for the whole set of training
samples. On the other hand, training samples must be linearly independent and
non-orthogonal. However, how failing to meet these requirements affects the
resulting QNN is not fully studied. To address this, we extend the proof of the
QNFL theorem to (i) provide a generalization of the theorem for varying degrees
of entanglement. This generalization shows that the average degree of
entanglement in the set of training samples can be used to predict the expected
quality of the QNN. Furthermore, we (ii) introduce new estimates for the
expected accuracy of QNNs for moderately entangled training samples that are
linear dependent or orthogonal. Our analytical results are (iii) experimentally
validated by simulating QNN training and analyzing the quality of the QNN after
training
GSMS and space views: Advanced spacecraft monitoring tools
The Graphical Spacecraft Monitoring System (GSMS) processes and translates real-time telemetry data from the Gamma Ray Observatory (GRO) spacecraft into high resolution 2-D and 3-D color displays showing the spacecraft's position relative to the Sun, Earth, Moon, and stars, its predicted orbit path, its attitude, instrument field of views, and other items of interest to the GRO Flight Operations Team (FOT). The GSMS development project is described and the approach being undertaken for implementing Space Views, the next version of GSMS, is presented. Space Views is an object-oriented graphical spacecraft monitoring system that will become a standard component of Goddard Space Flight Center's Transportable Payload Operations Control Center (TPOCC)
An Airborne Onboard Parallel Processing Testbed
This presentation provides information on the progress the Intelligent Payload Module (IPM) development effort. In addition, a vision is presented on integration of the IPM architecture with the GeoSocial Application Program Interface (API) architecture to enable efficient distribution of satellite data products
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