Search results for "NETWORK"
showing 10 items of 7718 documents
Discrete-Time Periodic Wavelet Packets
2014
Direct and inverse wavelet and wavelet packet transforms of a spline are implemented by filtering the spline’s coordinates by two-channel critically sampled p-filter banks. In this chapter, those p-filter banks are utilized for processing discrete-time signals. The p-filter banks generate discrete-time wavelets and wavelet packets in the spaces of 1D and 2D periodic signals.
Interference excision algorithm for frequency hopping spread spectrum based on undecimated wavelet packet transform
2002
An algorithm for reducing narrowband interference effects in frequency hopping spread spectrum is presented. The method is based on the undecimated wavelet packet transform. It improves the performance obtained by other methods. Experimental results demonstrate the suitability of the algorithm.
Digital background calibration algorithm and its FPGA implementation for timing mismatch correction of time-interleaved ADC
2019
Sample time error can degrade the performance of time-interleaved analog to digital converters (TIADCs). A fully digital background algorithm is presented in this paper to estimate and correct the timing mismatch errors between four interleaved channels, together with its hardware implementation. The proposed algorithm provides low computation burden and high performance. It is based on the simplified representation of the coefficients of the Lagrange interpolator. Simulation results show that it can suppress error tones in all of the Nyquist band. Results show that, for a four-channel TIADC with 10-bit resolution, the proposed algorithm improves the signal to noise and distortion ratio (SN…
Radio k-Labelings for Cartesian Products of Graphs
2005
International audience; Frequency planning consists in allocating frequencies to the transmitters of a cellular network so as to ensure that no pair of transmitters interfere. We study the problem of reducing interference by modeling this by a radio k-labeling problem on graphs: For a graph G and an integer k ≥ 1, a radio k-labeling of G is an assignment f of non negative integers to the vertices of G such that |f(x)−f(y)| ≥ k+1−dG(x,y), for any two vertices x and y, where dG(x,y) is the distance between x and y in G. The radio k-chromatic number is the minimum of max{f(x)−f(y):x,y ∈ V(G)} over all radio k-labelings f of G. In this paper we present the radio k-labeling for the Cartesian pro…
About the Stability of Active Queue Management Mechanism
2004
In this paper, we discuss the influence of multiple bottlenecks on the stability of Active Queue Management (AQM) controllers, usually configured on a single bottleneck basis. To see this, we consider a network scenario where RED is configured at each router according to previously developed control theoretic techniques. These configuration rules assure stability in a single bottleneck scenario. Yet, we show that instability may arise when two links become congested. We justify this result through a multiple bottleneck model.
AQM Generalized Nyquist stability in multiple bottlenecks networks
2005
The influence of multiple bottlenecks on the stability of Active Queue Management (AQM) controllers, usually configured on a single bottleneck basis is discussed. We consider a network scenario where RED is configured at each router according to previously developed control theoretic techniques. These configuration rules assure stability in a single bottleneck scenario. We show that instability may arise when two links become congested. We justify this result through a multiple bottleneck model using the Generalized Nyquist stability criterion.
Finite-time stability analysis and stabilization for linear discrete-time system with time-varying delay
2014
Abstract The problem of finite-time stability for linear discrete-time systems with time-varying delay is studied in this paper. In order to deal with the time delay, the original system is firstly transformed into two interconnected subsystems. By constructing a delay-dependent Lyapunov–Krasovskii functional and using a two-term approximation of the time-varying delay, sufficient conditions of finite-time stability are derived and expressed in terms of linear matrix inequalities (LMIs). The derived stability conditions can be applied into analyzing the finite-time stability and deriving the maximally tolerable delay. Compared with the existing results on finite-time stability, the derived …
INTER-ORGANIZATIONAL NETWORKS FOR INNOVATIONS AND SUSTAINABILITY
2021
The present Thesis is structured as a collection of three essays linked by one core idea: contributing to research knowledge on inter-organizational network dynamics in the context of innovation and the promotion of sustainability. In this Thesis, the author takes a systemic perspective and analyses the interactions between diverse groups of stakeholders, aiming to identify and interpret the logic underlying the formation of inter-organizational partnerships to promote innovation and sustainability. The dynamics of inter-organizational networks are influenced by several internal and external factors, such as strategic cooperation with stakeholders, structural changes (such as an R&I policy …
LoneStar RAID
2016
The need for huge storage archives rises with the ever growing creation of data. With today’s big data and data analytics applications, some of these huge archives become active in the sense that all stored data can be accessed at any time. Running and evolving these archives is a constant tradeoff between performance, capacity, and price. We present the LoneStar RAID, a disk-based storage architecture, which focuses on high reliability, low energy consumption, and cheap reads. It is designed for MAID systems with up to hundreds of disk drives per server and is optimized for “write once, read sometimes” workloads. We use dedicated data and parity disks, and export the data disks as individu…
VLPZ: The Vehicular Location Privacy Zone
2016
International audience; One of the key challenges in the success of vehicular ad hoc networks (VANETs) is to consider the location privacy of drivers. Although, the pseudonym changing approach is suggested by standardization development organizations such as IEEE and ETSI, the development of an effective pseudonym changing strategy is still an open issue. The existing pseudonym changing strategies are either not effective to protect against the pseudonyms linking attacks or can have a negative impact on the VANETs’ applications. To address these issues, this paper proposes a new pseudonym changing strategy based on the Vehicular Location Privacy Zone (VLPZ), which is a roadside infrastructu…