Effect of curvature on the backscattering from leaves

Using a model previously developed for the backscattering cross section of a planar leaf at X-band frequencies and above, the effect of leaf curvature is examined. For normal incidence on a rectangular section of a leaf curved in one and two dimensions, an integral expression for the backscattered field is evaluated numerically and by a stationary phase approximation, leading to a simple analytical expression for the cross section reduction produced by the curvature. Numerical results based on the two methods are virtually identical, and in excellent agreement with measured data for rectangular sections of coleus leaves applied to the surfaces of styrofoam cylinders and spheres of different radii

Partner selection in indoor-to-outdoor cooperative networks: an experimental study

In this paper, we develop a partner selection protocol for enhancing the network lifetime in cooperative wireless networks. The case-study is the cooperative relayed transmission from fixed indoor nodes to a common outdoor access point. A stochastic bivariate model for the spatial distribution of the fading parameters that govern the link performance, namely the Rician K-factor and the path-loss, is proposed and validated by means of real channel measurements. The partner selection protocol is based on the real-time estimation of a function of these fading parameters, i.e., the coding gain. To reduce the complexity of the link quality assessment, a Bayesian approach is proposed that uses the site-specific bivariate model as a-priori information for the coding gain estimation. This link quality estimator allows network lifetime gains almost as if all K-factor values were known. Furthermore, it suits IEEE 802.15.4 compliant networks as it efficiently exploits the information acquired from the receiver signal strength indicator. Extensive numerical results highlight the trade-off between complexity, robustness to model mismatches and network lifetime performance. We show for instance that infrequent updates of the site-specific model through K-factor estimation over a subset of links are sufficient to at least double the network lifetime with respect to existing algorithms based on path loss information only.Comment: This work has been submitted to IEEE Journal on Selected Areas in Communications in August 201

On Impedance Bandwidth of Resonant Patch Antennas Implemented Using Structures with Engineered Dispersion

We consider resonant patch antennas, implemented using loaded transmission-line networks and other exotic structures having engineered dispersion. An analytical expression is derived for the ratio of radiation quality factors of such antennas and conventional patch antennas loaded with (reference) dielectrics. In the ideal case this ratio depends only on the propagation constant and wave impedance of the structure under test, and it can be conveniently used to study what kind of dispersion leads to improved impedance bandwidth. We illustrate the effect of dispersion by implementing a resonant patch antenna using a periodic network of LC elements. The analytical results predicting enhanced impedance bandwidth compared to the reference results are validated using a commercial circuit simulator. Discussion is conducted on the practical limitations for the use of the proposed expression.Comment: 4 pages, 7 figure

Application of serious games to sport, health and exercise

Use of interactive entertainment has been exponentially expanded since the last decade. Throughout this 10+ year evolution there has been a concern about turning entertainment properties into serious applications, a.k.a "Serious Games". In this article we present two set of Serious Game applications, an Environment Visualising game which focuses solely on applying serious games to elite Olympic sport and another set of serious games that incorporate an in house developed proprietary input system that can detect most of the human movements which focuses on applying serious games to health and exercise

Assessment of hydrogen embrittlement of natural gas pipeline steels

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Diffraction of a Dipole Field by a Perfectly Conducting Half Plane

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116080/1/rds19672111339.pd

Plane wave solutions for right‐angled interior impedance wedges

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95650/1/rds5420.pd

Attention and visual memory in visualization and computer graphics

Abstract—A fundamental goal of visualization is to produce images of data that support visual analysis, exploration, and discovery of novel insights. An important consideration during visualization design is the role of human visual perception. How we “see ” details in an image can directly impact a viewer’s efficiency and effectiveness. This paper surveys research on attention and visual perception, with a specific focus on results that have direct relevance to visualization and visual analytics. We discuss theories of low-level visual perception, then show how these findings form a foundation for more recent work on visual memory and visual attention. We conclude with a brief overview of how knowledge of visual attention and visual memory is being applied in visualization and graphics. We also discuss how challenges in visualization are motivating research in psychophysics

Determining the impacts of environmental parameters on model microbial community dynamics isolated from Rustumihia WWTP/Iraq

The composition of Rustumihia microbial community and their diversity with oxylene-contaminants were investigated by applying molecular techniques - polymerase chain reaction and denaturing gradient gel electrophoresis (PCR and DGGE) - via investigating 16S rRNA gene fragments and understand the interrelationships between microbial community composition and structure for established microbial model community isolated from Rustumihia WWTP. To this end, the established consortium could be used to assess the microbial response as defined by diversity and richness shifts, which are linked to changes in growth conditions. In this research paper a synthetic consortium was created by isolating indigenous microbial community members from the Rustumihia WWTP and subjecting the consortium to different pH conditions (6.5, 7.0 and 7.5), o-xylene concentrations (0.5, 5 and 50 Mm) and temperatures (25°C, 35°C, 45°C and 55°C). The results of this study indicated that the high o-xylene concentration of 50 mM was tolerated and degraded effectively at 35°C and 55°C, and pH 6.5 (P < 0.001). Bacterial richness and diversity were recorded according to the Hill parameters of 0D, 1D and 2D under each of the growth conditions, and then linked to the o-xylene degradation efficiency. At 35°C and pH 6.5, the consortium achieved high degradation percentage for each of 0.5, 5 and 50 mM of o-xylene with values of 73.1%, 94.8% and 63.08%, respectively. The current study is the first of its kind in Iraq. It investigates the enrichment, isolation, and identification of a microbial community from the Rustumihia WWTP and determines the efficiency of the isolates to tolerate and degrade oxylene, highlighting their sole source of hydrocarbon. This research underscores the usefulness of molecular techniques for both diversity and richness to understand the ecological impact of o-xylene as a contaminant and to identify potential molecular techniques for detection of gene that is responsible for o-xylene degradation

An Energy and Performance Exploration of Network-on-Chip Architectures

In this paper, we explore the designs of a circuit-switched router, a wormhole router, a quality-of-service (QoS) supporting virtual channel router and a speculative virtual channel router and accurately evaluate the energy-performance tradeoffs they offer. Power results from the designs placed and routed in a 90-nm CMOS process show that all the architectures dissipate significant idle state power. The additional energy required to route a packet through the router is then shown to be dominated by the data path. This leads to the key result that, if this trend continues, the use of more elaborate control can be justified and will not be immediately limited by the energy budget. A performance analysis also shows that dynamic resource allocation leads to the lowest network latencies, while static allocation may be used to meet QoS goals. Combining the power and performance figures then allows an energy-latency product to be calculated to judge the efficiency of each of the networks. The speculative virtual channel router was shown to have a very similar efficiency to the wormhole router, while providing a better performance, supporting its use for general purpose designs. Finally, area metrics are also presented to allow a comparison of implementation costs