1,225 research outputs found
Chess Piece Detection
This project determines the positions of each piece on a physical chessboard, so that a computer can record a game of chess by noting down the piece positions at the end of each turn. It determines each move so that the game can be replayed later without watching actual footage. The project allows for easy viewing of past games. An image of the chessboard is analyzed to detect each square on the board, and each piece\u27s location. This is then done for each turn, so that the system can keep track of an entire game
Marshall Application Realignment System (MARS) Architecture
The Marshall Application Realignment System (MARS) Architecture project was established to meet the certification requirements of the Department of Defense Architecture Framework (DoDAF) V2.0 Federal Enterprise Architecture Certification (FEAC) Institute program and to provide added value to the Marshall Space Flight Center (MSFC) Application Portfolio Management process. The MARS Architecture aims to: (1) address the NASA MSFC Chief Information Officer (CIO) strategic initiative to improve Application Portfolio Management (APM) by optimizing investments and improving portfolio performance, and (2) develop a decision-aiding capability by which applications registered within the MSFC application portfolio can be analyzed and considered for retirement or decommission. The MARS Architecture describes a to-be target capability that supports application portfolio analysis against scoring measures (based on value) and overall portfolio performance objectives (based on enterprise needs and policies). This scoring and decision-aiding capability supports the process by which MSFC application investments are realigned or retired from the application portfolio. The MARS Architecture is a multi-phase effort to: (1) conduct strategic architecture planning and knowledge development based on the DoDAF V2.0 six-step methodology, (2) describe one architecture through multiple viewpoints, (3) conduct portfolio analyses based on a defined operational concept, and (4) enable a new capability to support the MSFC enterprise IT management mission, vision, and goals. This report documents Phase 1 (Strategy and Design), which includes discovery, planning, and development of initial architecture viewpoints. Phase 2 will move forward the process of building the architecture, widening the scope to include application realignment (in addition to application retirement), and validating the underlying architecture logic before moving into Phase 3. The MARS Architecture key stakeholders are most interested in Phase 3 because this is where the data analysis, scoring, and recommendation capability is realized. Stakeholders want to see the benefits derived from reducing the steady-state application base and identify opportunities for portfolio performance improvement and application realignment
Living with limited water: sunflowers and cotton as alternative crops
Presented at the 15th annual Central Plains irrigation conference and exposition proceedings on February 4-5, 2003 at the City Limits Convention Center in Colby, Kansas.Includes bibliographical references
Estimating Influenza Vaccine Efficacy From Challenge and Community-based Study Data
In this paper, the authors provide estimates of 4 measures of vaccine efficacy for live, attenuated and inactivated influenza vaccine based on secondary analysis of 5 experimental influenza challenge studies in seronegative adults and community-based vaccine trials. The 4 vaccine efficacy measures are for susceptibility (VES), symptomatic illness given infection (VEP), infection and illness (VESP), and infectiousness (VEI). The authors also propose a combined (VEC) measure of the reduction in transmission in the entire population based on all of the above efficacy measures. Live influenza vaccine and inactivated vaccine provided similar protection against laboratory-confirmed infection (for live vaccine: VES = 41%, 95% confidence interval (CI): 15, 66; for inactivated vaccine: VES = 43%, 95% CI: 8, 79). Live vaccine had a higher efficacy for illness given infection (VEP = 67%, 95% CI: 24, 100) than inactivated vaccine (VEP = 29%, 95% CI: −19, 76), although the difference was not statistically significant. VESP for the live vaccine was higher than for the inactivated vaccine. VEI estimates were particularly low for these influenza vaccines. VESP and VEC can remain high for both vaccines, even when VEI is relatively low, as long as the other 2 measures of vaccine efficacy are relatively high
Current status of live attenuated influenza vaccine in the United States for seasonal and pandemic influenza
A live attenuated influenza vaccine (LAIV) is currently approved in the United States for the prevention of influenza in individuals 2–49 years of age. This article summarizes the available data describing the safety and efficacy of LAIV for the prevention of influenza in both children and adults. LAIV is administered as an intranasal spray and has been shown to provide high levels of efficacy against influenza illness caused by both matched and mismatched strains in children and adults. In studies comparing LAIV and inactivated influenza vaccine in children, LAIV recipients experienced 35–53% fewer cases of culture-confirmed influenza illness caused by antigenically matched strains. Protection through a second influenza season against antigenically matched strains has also been seen in children. In adults, definitive comparative studies of LAIV and inactivated vaccine have not been conducted and no statistically significant differences in efficacy have been demonstrated. The most common adverse reactions with LAIV include runny nose/nasal congestion in all age groups, fever >100°F in children, and sore throat in adults. Formulations of LAIV against pandemic influenza strains, including H5N1, H9N2, and H7N3, are currently being tested in preclinical and phase I clinical studies
The relative efficacy of trivalent live attenuated and inactivated influenza vaccines in children and adults
In the United States, two types of vaccines are recommended for the prevention of influenza: an intranasal live attenuated influenza vaccine (LAIV) for eligible individuals aged 2–49 years and unadjuvanted injectable trivalent inactivated vaccines (TIV) for eligible individuals aged ≥6 months. Several recent studies have compared the efficacy of the 2 vaccines in children and adults. In children 6 months to 18 years of age, each of the four comparative studies of LAIV and TIV demonstrated that LAIV was more protective. In individuals 17–49 years of age, most comparative studies have demonstrated that LAIV and TIV were similarly efficacious or that TIV was more efficacious. However, LAIV was shown to be more protective than TIV in new military recruits of all ages, and placebo-controlled studies in adults in 1997–1998 suggested that LAIV was more protective against the mismatched A/H3N2 strain. The relative efficacy of LAIV and TIV among young adults may vary depending on the specific population and the antigenic match between the vaccines and circulating strains. In adults 60 years of age and older, limited data suggest that the two vaccines are similarly effective. In children and adults, studies also suggest that the relative efficacy of LAIV versus TIV may increase when measured against more severe illness. Additional research comparing LAIV and TIV is needed in adults and would also be valuable in older children and adolescents. Studies should examine the role of pre-existing immunity as well as vaccine impact on influenza illness of varying severity
QUIC-FEC: Bringing the benefits of Forward Erasure Correction to QUIC
Originally implemented by Google, QUIC gathers a growing interest by
providing, on top of UDP, the same service as the classical TCP/TLS/HTTP/2
stack. The IETF will finalise the QUIC specification in 2019.
A key feature of QUIC is that almost all its packets, including most of its
headers, are fully encrypted. This prevents eavesdropping and interferences
caused by middleboxes. Thanks to this feature and its clean design, QUIC is
easier to extend than TCP. In this paper, we revisit the reliable transmission
mechanisms that are included in QUIC. More specifically, we design, implement
and evaluate Forward Erasure Correction (FEC) extensions to QUIC. These
extensions are mainly intended for high-delays and lossy communications such as
In-Flight Communications. Our design includes a generic FEC frame and our
implementation supports the XOR, Reed-Solomon and Convolutional RLC
error-correcting codes. We also conservatively avoid hindering the loss-based
congestion signal by distinguishing the packets that have been received from
the packets that have been recovered by the FEC. We evaluate its performance by
applying an experimental design covering a wide range of delay and packet loss
conditions with reproducible experiments. These confirm that our modular design
allows the protocol to adapt to the network conditions. For long data transfers
or when the loss rate and delay are small, the FEC overhead negatively impacts
the download completion time. However, with high packet loss rates and long
delays or smaller files, FEC allows drastically reducing the download
completion time by avoiding costly retransmission timeouts. These results show
that there is a need to use FEC adaptively to the network conditions.Comment: 9 pages, presented at IFIP Networking 201
Evaluating pulse-amplitude modulated fluorometry for landscape scale assessment of photosynthetic characteristics
Pulse-amplitude modulated fluorometry (PAM) was evaluated for monitoring the physiological condition of the seagrass, Thalassia testudinum, in Florida Bay. This approach is attractive because it is rapid, non-invasive, and offers quantitative physiological information. Yet, problems arise when expanding sampling from the organismal scale to the landscape scale, due to temporal changes in photophysiology. The magnitude of diurnal variation of photosynthetic characteristics was investigated using Rapid Light Curves (RLC), which measure quantum yield over a range of changing actinic irradiances. In this study, the resulting calculated parameters (alpha and ETRmax) significantly changed diurnally, as was previously found with effective quantum yield. The significance of among basin and year comparisons was also confounded by diurnal variation and rigorous statistical analysis was unable to discern which time of day was best suited for assessing the photophysiological status of T. testudinum. Even though measurements taken with PAM fluorometry exhibited a significant amount of diurnal noise, informative physiological patterns did emerge. The ability to distinguish among basins and see landscape scale trends within the bay gives us an indication that PAM fluorometry may be useful as a monitoring tool. However, in ecosystems where the magnitude of changes are large and occur on much faster timescales than the ecosystem changes that you are trying to measure, the resulting fluctuations may obscure the true physiological signal. Therefore, when using this approach over large spatial and temporal scales diurnal variability must be considered.
In order to incorporate the entire temporal and spatial scale two previously proposed methods, the Diel Yield and Diel Rapid Light Curve method, were investigated. Photosynthesis irradiance (P-E) curves were calculating using both methods and the ability of each method to accurately predict the relationship between electron transport and irradiance was explored. It was found that neither method was able to provide consistent estimates of photosynthetic efficiency or capacity. The Diel Yield method frequently produced unrealistic predictions of photosynthetic capacity (rETRmax) and saturation irradiance (Ik). The Diel RLC method produced more reasonable predictions of rETRmax and Ik, but this method had the most difficulty predicting photosynthetic efficiency (alpha) when ambient irradiances were continuously high throughout the day (>Ik). With some further calculations we believe the Diel RLC method can provide an estimate of photosynthetic efficiency and offer a way to reasonably approximate landscape-level photosynthetic characteristics. Because both methods investigated in this study use data generated from RLCs, which have been shown to vary depending on previous light history; diurnal variations do affect estimates of electron transport rates. Therefore, the Diel RLC method does not negate diurnal variation but it does produce a curve that incorporates the changing ambient light environment
Local Victory: Assessing Interspecific Competition in Seagrass From a Trait-Based Perspective
Tropical seagrass meadows are formed by an array of seagrass species that share the same space. Species sharing the same plot are competing for resources, namely light and inorganic nutrients, which results in the capacity of some species to preempt space from others. However, the drivers behind seagrass species competition are not completely understood. In this work, we studied the competitive interactions among tropical seagrass species of Unguja Island (Zanzibar, Tanzania) using a trait-based approach. We quantified the abundance of eight seagrass species under different trophic states, and selected nine traits related to light and inorganic nutrient preemption to characterize the functional strategy of the species (leaf maximum length and width, leaves per shoot, leaf mass area, vertical rhizome length, shoots per meter of ramet, rhizome diameter, roots per meter of ramet, and root maximum length). From the seagrass abundance we calculated the probability of space preemption between pairs of seagrass species and for each individual seagrass species under the different trophic states. Species had different probabilities of space preemption, with the climax species Thalassodendron ciliatum, Enhalus acoroides, Thalassia hemprichii, and the opportunistic Cymodocea serrulata having the highest probability of preemption, while the pioneer and opportunistic species Halophila ovalis, Syringodium isoetifolium, Halodule uninervis, and Cymodocea rotundata had the lowest. Traits determining the functional strategy showed that there was a size gradient across species. For two co-occurring seagrass species, probability of preemption was the highest for the larger species, it increased as the size difference between species increased and was unaffected by the trophic state. Competitive interactions among seagrass species were asymmetrical, i.e., negative effects were not reciprocal, and the driver behind space preemption was determined by plant size. Seagrass space preemption is a consequence of resource competition, and the probability of a species to exert preemption can be calculated using a trait-based approach
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