A slotted packet broadcast channel with an infinite user population is considered. A limited feedback sensing algorithm is proposed and analyzed for collision versus noncollision binary feedback. The algorithm bas max...
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A slotted packet broadcast channel with an infinite user population is considered. A limited feedback sensing algorithm is proposed and analyzed for collision versus noncollision binary feedback. The algorithm bas maximum throughput equal to 0.42 (packets/slot), has uniformly good delay characteristics within its stability region, and is robust in the presence of feedback errors. A variation of the algorithm, for ternary feedback, attains maximum throughput 0.425 and bas uniformly good delay characteristics within its stability region. In contrast, the highest throughput limited feedback sensing algorithm existing for ternary feedback attains maximum throughput 0.456 , but induces relatively high delays for Poisson intensities below 0.3 .
In this paper, a new numerical method for determining effective permittivity of dense random media in two dimensions is presented, The core of the method is to compare the average scattered field of a random collectio...
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In this paper, a new numerical method for determining effective permittivity of dense random media in two dimensions is presented, The core of the method is to compare the average scattered field of a random collection of scatterers confined within an imaginary boundary with the scattered field from a homogeneous dielectric of the same shape as the imaginary boundary, The two-dimensional (2-D) problem is aggressively studied here to provide insight into the dependence of the method's convergence on particle size, boundary shape, and boundary dimension. A novel inverse scattering method is introduced based on the method of moments (MoM), which greatly reduces the computation time and increases the flexibility of the procedure to analyze a variety of geometries. Results from this 2-D method may be used directly to compare with theoretical methods for determining effective permittivity such as the Polder-Van Santen mixing formula or field techniques such as the quasi-crystalline approximation.
A new algorithm to convert the discrete cosine transform (DCT) to skew-circular convolutions is presented. The motivation for developing such an algorithm is the fact that VLSI implementation of distributed arithmetic...
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A new algorithm to convert the discrete cosine transform (DCT) to skew-circular convolutions is presented. The motivation for developing such an algorithm is the fact that VLSI implementation of distributed arithmetic is very efficient for computing convolutions. It is also shown that the inverse DCT (IDCT) can be computed using the same building blocks which are used for computing the DCT. A DCT/IDCT processor can be designed to compute either the DCT or the IDCT depending on a single line control signal.
In this paper, a random, conflict-free slot assignment policy is adopted for the allocation of a common channel between two (non-communicating) stations. Although this policy is inferior to the optimal periodic, fixed...
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In this paper, a random, conflict-free slot assignment policy is adopted for the allocation of a common channel between two (non-communicating) stations. Although this policy is inferior to the optimal periodic, fixed slot assignment policy, it is shown than it achieves the performance of that optimal policy as the variance of the packet arrival process increases. The main advantage of the random, conflict-free slot assignment policy is that it is simple and always feasible unlike the optimal, periodic, fixed slot assignment policy. Furthermore, the proposed policy is easily implemented in a dynamically changing environment;the optimal such policy is derived and a simple strategy based on a threshold test is developed for the identification of the optimal such policy, when estimates of the traffic parameters are available. No such strategy is known for the adaptation of the parameters of the optimal periodic, fixed slot assignment policy. The developed analysis approach can be applied, to a great extent, to a system with more than two stations.
Unmanned Ariel Vehicles(UAVs)are flying objects whose trajectory can be remotely *** have lot of potential applications in the areas of wireless communications,internet of things,security,traffic management,monitoring...
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Unmanned Ariel Vehicles(UAVs)are flying objects whose trajectory can be remotely *** have lot of potential applications in the areas of wireless communications,internet of things,security,traffic management,monitoring,and smart *** enabling reliable communication between UAVs and ground nodes,emergency notifications can be efficiently and quickly disseminated to a wider *** can gather data from remote areas,industrial units,and emergency scenarios without human *** can support ubiquitous connectivity,green communications,and intelligent wireless resource *** efficiently use UAVs for all these applications,important challenges need to be *** this paper,we first present a detailed classification of UAVs based on factors such as their size,communication range,weight,and flight *** also explain the hardware system configuration and uses of these *** present a brief overview of recent work done related to three major challenges in *** challenges include trajectory control,energy efficiency and resource *** also present three open challenges and future opportunities for efficient UAV *** include use of learning algorithms for resource allocation and energy efficiency in UAVs,intelligent surfaces-based communications for enhanced reliability in UAVs,and security algorithms to combat malicious attacks against UAVs.
In this paper, we propose a range reconstruction method for a frequency-band shared multipleinput multiple-output(MIMO) orthogonal frequency-division multiplexing(OFDM) radar with sufficient cyclic prefix(CP) by using...
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In this paper, we propose a range reconstruction method for a frequency-band shared multipleinput multiple-output(MIMO) orthogonal frequency-division multiplexing(OFDM) radar with sufficient cyclic prefix(CP) by using real orthogonal designs. Compared with the application of complex orthogonal designs in our previous work, the application of real orthogonal designs can significantly reduce the number of the all-zero-valued pulses in a coherent processing interval(CPI) for each transmitter and increase the efficiency of radar transmitters. Meanwhile, it still maintains the advantages of full spatial diversity without inter-range-cell interference(IRCI). We also apply the rate-1 real orthogonal designs for different numbers of transmitters and pulses for range reconstruction without any idleness of radar transmitters. Simulation results are presented to illustrate the performances of the OFDM pulse design and the CP-based MIMO OFDM radar using real orthogonal designs.
Sequential networks contain combinational logic blocks separated by registers. Application of combinational logic minimization techniques to the separate logic block results in improvement that is restricted by the pl...
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Sequential networks contain combinational logic blocks separated by registers. Application of combinational logic minimization techniques to the separate logic block results in improvement that is restricted by the placement of the registers; information about logical dependencies between blocks separated by registers is not utilized. Temporarily moving all the registers to the periphery of a network provides the combinational logic minimization tools with a global view of the logic. A technique is proposed for optimizing a sequential network by moving the registers to the boundary of the network using an extension of retiming, resynthesizing the combinational logic between the registers using existing logic minimization techniques, and replacing the registers throughout the network using retiming algorithms.< >
In many RFID-enabled applications, objects are classified into different categories, and the information associated with each object's category (called category information) is written into the attached tag, allow...
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This paper proposes a hierarchical approach to solving the surface and vertex correspondence problems in multiple-view-based three-dimensional object recognition systems. The proposed scheme is a coarse-to-fine search...
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This paper proposes a hierarchical approach to solving the surface and vertex correspondence problems in multiple-view-based three-dimensional object recognition systems. The proposed scheme is a coarse-to-fine search process and a Hopfield network is employed at each stage. Compared with conventional object matching schemes, the proposed technique provides a more general and compact formulation of the problem and a solution more suitable for parallel implementation. At the coarse search stage, the surface matching scores between the input image and each object model in the database are computed through a Hopfield network and are used to select the candidates for further consideration. At the fine search stage, the object models selected from the previous stage are fed into another Hopfield network for vertex matching. The object model that has the best surface and vertex correspondences with the input image is finally singled out as the best matched model. Experimental results are reported using both synthetic and real range images to corroborate the proposed theory.
Switched-capacitor (SC) filters continue to improve in performance mainly through progress in the design of MOS operational amplifiers (op amps). Ultimate limits to achievable filter performance, however, stem from fa...
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Switched-capacitor (SC) filters continue to improve in performance mainly through progress in the design of MOS operational amplifiers (op amps). Ultimate limits to achievable filter performance, however, stem from factors more fundamental than op amp nonidealities, factors independent of process and circuit improvements. This paper develops, from certain basic assumptions, ultimate limits on dynamic range, chip area, and power consumption in SC integrators and low-pass filters. For integrators, minimum area and power requirements are shown to vary as the square of desired dynamic range. Some physically realistic approximations lead to expressions relating filter area, power consumption, and dynamic range which involve only fundamental process parameters, supply voltage and filter cut-off frequency. Comparison with actual performance in typical commercially manufactured SC filters suggests that there is still a strong motivation in improving op amp specifications. A typical commercial fifth-order voiceband filter operating from a\\pm 5-Vsupply with a dynamic range of 95 dB consumes approximately 5 mW and requires an area of approximately5000 {mil}^{2}compared with the theoretical minima of8.5 \\mu Wand11.2 {mil}^{2}, respectively.
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