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This paper discusses the design of a wide-bandwidth, wide-beamwidth, cavity-backed Archimedean spiral antenna for use in 10–40 GHz holographic radar imaging arrays. Simulated and measured performance characteristics are presented along with millimeter-wave radar images obtained with the antenna arrays for security screening applications.
For a formula F in conjunctive normal form (CNF), let sat(F) be the maximum number of clauses of F that can be satisfied by a truth assignment, and let m be the number of clauses in F. It is well-known that for every CNF formula F, sat(F) ≥ m/2 and the bound is tight when F consists of conflicting unit clauses (x) and $(\bar{x})$ . Since each truth assignment satisfies exactly one clause in each...
In the problem Max Lin, we are given a system Az = b of m linear equations with n variables over in which each equation is assigned a positive weight and we wish to find an assignment of values to the variables that maximizes the excess, which is the total weight of satisfied equations minus the total weight of falsified equations. Using an algebraic approach, we obtain a lower bound...
Let F be a CNF formula with n variables and m clauses. F is t-satisfiable if for any t clauses in F, there is a truth assignment which satisfies all of them. Lieberherr and Specker (1982) and, later, Yannakakis (1994) proved that in each 3-satisfiable CNF formula at least of its clauses can be satisfied by a truth assignment. Yannakakis’s proof utilizes the fact that ...
Pneumatic conveying has become a well established method of transporting materials in the resource and process industries. Erosion is a phenomenon that occurs in pneumatic conveying pipeline due to the inherent nature of conveying process. In pneumatic conveying, particulate material is transported by the motive of compressed gas with velocities usually less than 60 m/s. In the present investigation,...
A commonly recognised and significant problem faced by those suffering from addiction to drugs and alcohol and other substances (or repetitive patterns of behaviour) is the lack of easily accessed, educational technologies currently available to them. Recovery based material exists but there is no cohesive option which is able to offer a fully multi-media opportunity for: self-reflection, communication...
Within any organization there is a need to assess the level of maturity of developing technologies and identify at what level they are fit for deployment in real application. TRLs were first developed by NASA over 25 years ago to prove a technology was suitable and reliable enough for the integration into space systems. This TRL scale has now been developed and adapted to suit the aerospace industry...
A fundamentally different approach to broadband array design has been developed and validated with measured hardware. Traditional array design is based on designing an isolated element with the desired bandwidth and radiation characteristics and does not account for the mutual coupling that occurs when this element is placed in an array environment. It is well known that undesired mutual coupling...
This article consists of a collection of slides from the author's conference presentation on Ambric's TeraOPS hardware, a parallel MIMD computing fabric for integrated circuits. Some of the specific topics discussed include: the special features and architecture of TeraOPS; deployment and applications for its use; processing capabilities; facilities for object programming; programming model and tools;...
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