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Software Defined Radio (SDR) allows dynamically changing protocols and functions in order to provide flexible, multiple-standard services to users. A reconfigurable baseband architecture having a set of coarse-grained, heterogeneous execution units is one strategy which can meet this requirement. However, while we can integrate a large number of execution units onto a chip, conventional bus structures...
This paper proposes a local polynomial modeling approach and bandwidth selection algorithm for estimating time-varying linear models (TVLM). The time-varying coefficients of a TVLM are modeled locally by polynomials and estimated using least-squares estimation with a kernel having a certain bandwidth or support. Asymptotic behavior of the proposed estimator is established and it shows that there exists...
Speech has recently been recognized as an attractive method for the measurement of cognitive load. Current speech-based cognitive load measurement systems utilize acoustic features derived from auditory-motivated frequency scales. This paper aims to investigate the distribution of speech information specific to cognitive load discrimination as a function of frequency. We found that this distribution...
We propose and demonstrate a technique on chromatic dispersion (CD) insensitive polarization mode dispersion (PMD) monitoring based on RF tone power measurement using a narrow band fiber Bragg grating (FBG) notch filter. By filtering out the optical component at 10-GHz (1/4 of the bit rate) away from the carrier in one sideband, the RF tone generated by beating between the carrier and the component...
Real time network applications require effective mechanisms for managing Internet traffic in order to avoid or at least limit the level of congestion. We propose, design and analyze an Active Queue Manager (AQM) for controlling jitter using robust control theory. We used an output feedback controller and this controller is based on discrete-time model of TCP. The natural properties of robust controller...
BitTorrent is the dominating protocol in nearly all regions. Various reputation models and incentive mechanisms are proposed in recent years. However, many of them are designed for general peer-to-peer networks, only a few are designed for BitTorrent even though some models and mechanisms assert that they can be applied to BitTorrent-like systems. In this paper, we propose an incentive framework based...
To more effectively use a network of high performance computing clusters, allocating multi-process jobs across multiple connected clusters, i.e., job co-allocation, offers the possibility of more efficient use of computer resources, reduced turn-around time and computations using numbers of processes larger than processors on any single cluster. Effective co-allocation, ultimately, depends on the...
In this paper, two different types of Vivaldi antenna are designed and tested suitable for electromagnetic beamforming. The first is an antipodal Vivaldi antenna, while the other is a tapered slot Vivaldi antenna. They are both ultra wideband antennas for the 1 GHz to 5 GHz frequency band. They have low impulse distortion and the voltage standing wave ratio (VSWR) less than 2 throughout the entire...
A printed monopole antenna of the tapered and notched radiator with the microstrip feed-line is designed. The simulated and measured results show that the printed antenna achieves a broad impedance bandwidth of 3.1-11.1 GHz for the 10-dB return loss. This antenna features the stable omni-directional radiation patterns over the impedance bandwidth. Using the current distribution modes the influence...
Wireless ad hoc networks using omni-directional antennas do not scale well due to interference between nearby nodes. Maintaining the QoS of the communications in this type of network is a difficult task. Using multiple narrow beam directional antennas alleviates this problem at the expense of connectivity. Multi-beam smart antennas allow the network topology to be adjusted dynamically by adjusting...
A very simple method to demodulate the digital frequency modulated (FM) signal is presented in this paper. A unit delay operator, multiplier, lowpass filter, arccosine function, and adder are employed. The proposed method is easily adjusted and controlled. The computer simulations are conducted to demonstrate the performance of the proposed technique.
We proposed a fuzzy-logic-based dynamic bandwidth allocation (FLDBA) algorithm for upstream Ethernet passive optical network (EPON). In the proposed DBA algorithm, the optical line terminal allocates bandwidth to the optical network units in proportion to the priority category of the traffic class. Simulations were performed to prove the accuracy of the FLDBA algorithm by comparing the algorithm with...
In this paper, an all optical wavelength multicasting service in AWG-based WDM PON is introduced, and a novel architecture supporting multiple multicasting groups is proposed. The novel characteristic is that different from the PON systems which broadcast the signals to all the receivers, multicasting signals are only delivered to desired users. This restricted member multicasting brings the trusted...
Task Graphs is a commonly used application model in research in computer-aided design tools for design space exploration of embedded systems, including system synthesis, scheduling and application mapping. These design tools need an estimate of the actual communication in the target system caused by the application modelled by the task graph. In this paper, we present a method for analytically deriving...
In this paper, we present a new wideband low noise amplifier which operate in UHF band for spectral sensing in the receiver of cognitive radios. The circuit employs the noise-canceling technique, and can achieve the higher gain and lower power dissipation. The method of shunt-resistive feedback is adopted for achieving a broad bandwidth. The LNA is designed by the CMOS 0.18 um RF technology. Simulated...
This paper proposes the design and analysis of a broadband 2-40 GHz passive distributed drain-pumped mixer using 0.18 μm CMOS technology for ultrawide-band (UWB) receivers. To achieve broad bandwidth for the UWB communications, a distributed topology is introduced. A closed-form analytical model for the conversion loss of distributed drain-pumped mixer is presented for the first time. The designed...
This paper proposes a design methodology for solving a multi-objective circuit design problem, which is based on formulating the problem as a multi-objective geometric program (MOGP) with variable weight factors. In general, to solve the problem using GP, multiple objectives are combined into a scalar objective by assigning arbitrary, fixed weight factors to individual objectives. On the contrary,...
Different propagation mechanisms of the transmitted signal take place from the surrounding objects in an indoor scenario. The prediction of the reflection phenomenon is one of the important parameter of the ultra wideband (UWB) channel modeling. This paper presents a model of wave propagation in indoor environments for multiple reflections of UWB signal inside the building wall. The main objective...
A GALS Networks-on-Chip (NoC) router with QoS support is presented. It supports multi-levels of QoS including hard guarantees (Hard GT)and statistical guarantees (Soft GT). In hard GT, novel Rate-control schedule is adopted to decouple the relationship between bandwidth and delay. And then, different from other routers whose bandwidth left was absorbed by only BE packets, we also support soft GT to...
A BiCMOS integrated optical receiver with high sensitivity and linearity is presented. An automatic gain control transimpedance amplifier and linear post amplifiers are used to maintain a high linearity with multilevel modulation. Using multilevel signaling and large-diameter integrated photodiodes make the presented optical receiver suitable for small-bandwidth high-attenuation large-core PMMA step...
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