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A novel broadband millimeter-wave FLAPS reflector antenna with three types elements has been presented. The progressive phase shift is achieved by square-annular patches, combined patches and rectangle patches. The choice of this three types elements can make the phase shift smoother and increased up to 360??. Using this technique, a 15??-beam-steering FLAPS reflector antenna operating at 95 GHz is...
We present an analysis of the sound field of a moving sound source reconstructed from recordings of a virtual dual-radius open-sphere microphone array. As a consequence of the discrete property of such microphone distributions artifacts arise, most notably spatial aliasing and spatial bandwidth limitation artifacts. We show that these artifacts are much more pronounced for moving sound sources than...
The policy-managed radio model offers a way to force cognitive radios to comply with transmission restrictions and regulations. Policies that implement radio regulations are written in a policy language, and used by the policy engine to approve or deny transmission parameters. Since decision speed is one of the primary design requirements of cognitive radios, policy engines and reasoners can easily...
This paper proposes three novel admission control schemes for networks supporting prioritized advance reservation. The integer linear programming model for prioritized advance reservation and the pseudo-code algorithms implementing the schemes are outlined. Detailed simulation analysis results are then presented to compare the performance of the proposed schemes under different network load scenarios.
This paper describes our winning submission for the Absolute Performance category of the MEMOCODE 2009 Design Contest. We show that our GPGPU-based design achieves performance within a factor of four of theoretical maximum performance for the implemented algorithm. This result was reached after a short design-cycle of 2 man-days, which indicates that the NVIDIA CUDA platform allows for rapid development...
An ultra-wideband antenna array design concept is presented that achieves the same functionality of traditional single-element-based ultra-wideband arrays using multiple elements that are scaled in size from the base high-frequency element, resulting in significantly fewer elements overall. This novel array design leads to a significant reduction in weight and most importantly - a significant reduction...
A 9 X 13 printed microwave lens beam former was investigated numerically using MoM, and good performance was predicted across the quadruple band 6 GHz - 25 GHz. TTD behavior across entire band was achieved by array factor comparisons, with good beam quality demonstrations. Future work on this lens will involve the power efficiency study and prototype measurement validations.
The design of a Ka-band coplanar waveguide slot-coupled patch antenna ESA with integrated MEMS phase shifters has been described above. The incorporation of MEMS phase shifters into the ESA design results in a compact, efficient uplink mechanism for a future Army satellite communication system. A control board for biasing the phase shifters and initiating beam steering will be incorporated into the...
The idea of using element rotation to provide phase shift for circularly polarized (CP) reflectarray antennas is studied here. Investigations on these antenna sub-types often involve element design and the simulation as well as measurement of phase shifting properties using a waveguide simulator. Modern refiectarray antennas are typically fabricated using dielectric laminates. For passive elements,...
In this paper the design of a dual-polarization Ka-band array with a hybrid E-plane waveguide/stripline series feeding network has been presented. Preliminary measurements have shown satisfactory results, making the structure attractive in terms of efficiency and bandwidth performances.
Presented here is a design for an all-metal ultra-wideband antenna element that can achieve bandwidth of 12:1. While the design itself is worth reporting in its own right, this array element was designed as part of a study on low-cost ultra- wide bandwidth arrays reported here. For more robust design validations, finite array simulations will also be performed to mimic the set of S-parameters collected...
The four-aperture element for the double-layer corporate-feed hollow waveguide slot array has reflection below -15 dB over 9.5% bandwidth assuming the mutual couplings by the periodic boundary walls.
This paper reports two novel algorithms based on time-modulo reconstruction method intended for detection of the parametric faults in analogue-to-digital converters (ADC). In both algorithms, a pulse signal, in its slightly adapted form to allow sufficient time for converter settling, is taken as the test stimulus reliving the burden placed on accuracy requirement of excitation source. The objective...
The Cray XMT provides hardware support for parallel algorithms that would be communication- or memory-bound on other machines. Unfortunately, even if an algorithm meets these criteria, performance suffers if the algorithm is too numerically intensive. We present a lookup-based approach that achieves a significant performance advantage over explicit calculation. We describe an approach to balancing...
Classic vector systems have all but vanished from recent TOP500 lists. Looking at the newly introduced NEC SX-9 series, we benchmark its memory subsystem using the low level vector triad and employ an advanced lattice Boltzmann flow solver kernel to demonstrate that classic vectors still combine excellent performance with a well-established optimization approach. Results for commodity x86-based systems...
Linear algebra algorithms are fundamental to many computing applications. Modern GPUs are suited for many general purpose processing tasks and have emerged as inexpensive high performance co-processors due to their tremendous computing power. In this paper, we present the implementation of singular value decomposition (SVD) of a dense matrix on GPU using the CUDA programming model. SVD is implemented...
Data dissemination in the existing peer-to-peer multicast protocols is performed from source node by delivering data to destination nodes over either a tree or a partial-mesh path structure covering all the multicast nodes. In this paper, we show that the existing tree-based or partial-mesh-based data dissemination algorithms do not perform efficiently in traditional customer-provider networks. We...
As a prosperous technology for ending-phase Internet access, Worldwide interoperability for Microwave Access (WiMAX) appeals concentration throughout the world since there are some places where wired infrastructures are not available. However, Call Admission Control (CAC) is critical to control different traffic loads and prevent the network from being blocked in WiMAX environment. In our paper, a...
Four acousto-optic (AO) transducer designs have had their electronic operation bandwidths (BW) for the first order diffraction efficiency compared. The four designs are: (A) simple uniform sound field, (B) Hamming apodization, (C) uniform sound field with phased array (D) Hamming apodization of the sound field combined with a phased array. A Strong-AO-interaction two-order numerical analysis is applied...
This paper performs a parametric investigation into a couple of factors that influence the bandgap properties of electromagnetic bandgap (EBG) structures. The most common and easily fabricated grounded square-patch array is showcased here, and the two parameters investigated are the patch size relative to the unit cell and the dielectric slab thickness. It will be shown how a numerical search using...
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