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This paper deals with the problem of the loss of performance of the pair observer-controller, when measurements have a delay due to communication over networks. Here we consider the case where the estimation of the states is carried out using a moving horizon estimator (MHE), the control actions are computed by using a centralized model predictive controller (MPC), and the delay varies randomly and...
We consider several stability properties in the framework of input-to-state stability for time-varying systems with delays. By following a natural approach to convert a time-varying system to an auxiliary time-invariant system, we obtain several results including Razumikhin-type stability criteria, Razumikhin-Lyapunov functions with non-strict decay rates, and cyclic small-gain theorems for time-varying...
This paper is concerned with the problem of H∞ filter design for linear continuous-time state-delayed systems with finite frequency specifications. The developed approaches in the paper are to design a filter guaranteeing an H∞ performance bound in a finite frequency range for delayed systems. To reduce conservatism, delay-partitioning idea is exploited to derive a new finite frequency bounded real...
Explicit feedback based congestion control schemes can capture network congestion status more accurately than pure end-to-end schemes. However, some of such schemes require modifying IP header in order to achieve near optimal performance, which incurs complicated computation in routers as well as makes them difficult to deploy in real networks. In contrast, the VCP protocol achieves good performance...
Time delay estimation is important task in many signal processing application. Cost function parameter is used for estimating true delya's. In this paper we have modified the cost function by taking into account the low pass filtering characteristics of channel. Results obtained are calculated with the help of accuracy percentage.
In this paper we explore the impact of data encoding on the design of arithmetic circuits based on residue number system (RNS). Specifically, we show that departing from the conventional representation of residues as integers in weighed binary format and appropriately selecting a non-weighed encoding, efficient circuits in terms of power, area and performance are possible. A quantitative analysis...
In this paper, the problem of identification and recognition of an unknown source of experimental seismic vibrations in real time is described. The influence of different signal delays on frequency spectrum as well as autocorrelation and crosscorrelation functions is examined. It is also illustrated what is the effect of different pulse width on spectrum and correlation functions.
In sensor networks, small sensor nodes which are distributed in an area send various data and send them to the sink node by multi-hop transmission. The sensor networks cover various application fields such as safety management, health management, grasping of nature environment, military and so on. The sensor networks will be used as a technique for constructing ubiquitous society because of low cost...
OFDM signal classification has become an important requirement in many cognitive radios and military systems. Implementing such a requirement under Frequency Selective Rayleigh fading is a challenging task. In this paper, we explore different blind OFDM parameter and channel estimation techniques based on Maximum Likelihood techniques and higher order signal processing to ascertain the reception of...
While wireless sensor network aided robots lend humans a hand in accessing to certain difficult and/or otherwise unreachable areas, the robots may face challenges in locomotion, object discovering, searching and tracking among many demanding tasks. The unreliable wireless communication and possible components failures of wireless sensor nodes coupling with the noises in the uncertain environments...
In sensor networks, small sensor nodes which are distributed in an area send various data and send them to the sink node by multi-hop transmission. The sensor networks cover various application fields such as safety management, health management, grasping of nature environment, military and so on. The sensor networks will be used as a technique for constructing ubiquitous society because of low cost...
Deployment of femtocells with open or hybrid access into mobile networks leads to problems with handling handover of mobile users. In this paper we discuss two important aspects that can be considered and exploited in a design of innovative handover procedure for scenario with femtocells. The first aspect is related to varying quality and limited capacity of femtocell's backbone. Further, an accuracy...
QoS routing protocol has become a hot research spot. However, it is difficult to offer guaranteed QoS, such as bandwidth, delay and delay jitter. To solve this problem, we proposed a Delay-Minimized Routing protocol based on Bandwidth Estimation (DMR-BE) that incorporates an admission control scheme and a route decision scheme to meet the QoS requirement of bandwidth and real-time applications. Bandwidth...
Service providers offering IP-based video on demand services often replicate video content in multiple content servers with different network points of attachment. When a request for a content item arrives from an end-user, a decision must be made as to whether the request should be admitted and, if so, which server should be used. To ensure adequate quality-of-service this admission control / server...
In 3G long term evolution (LTE) systems, the random access channel (RACH) is used for initial access, resource request, and handover. Since the random access delay is determined by the arrival rate of the random access preambles and the number of RACH subframes, we should configure the number of RACH subframes given the arrival rate in order to guarantee the delay performance. In this work, by carefully...
Infrastructure-based mobile networks are becoming increasingly overloaded due to strong growing number of mobile devices like smartphones and their communication needs. Especially in urban cities the cost of maintaining and extending infrastructure is high due to increased geographical density of mobile devices. While this increasing density puts high load on infrastructure-based networks, it is an...
In this paper, a novel rapid varying doubly-selective channel estimator for OFDM systems has been proposed, in which channel is modeled by basis expansion model (BEM). Unlike traditional BEM channel estimation algorithms, in which the comb-pilot is used and the large path delay is not considered, the proposed algorithm uses firstly block-type pilot to estimate the BEM coefficients of fast-varying...
Several Tranmission Control Protocols have been proposed to address the significant problem on congestion control avoidance in order to be efficient in achieving high throughput on high-speed network in non-intrusive manner. TCP RAPID has recently been proposed as a new TCP that can search and adapt to the available bandwidth within a few RTT. RAPID is an outstanding protocol in many aspects especially...
As wireless and mobile technologies are becoming increasingly pervasive, an uninterrupted connectivity in mobile devices is becoming a necessity rather than a luxury. When dealing with challenged networking environments, this necessity becomes harder to achieve in the absence of end-to-end paths from servers to mobiles. One of the main techniques employed to such conditions is to simultaneously use...
The Forthroid is a location-based system that “augments” physical objects with multimedia information and enables users to receive information about physical objects or request services related to physical objects. It employs computer-vision techniques and Quick Response codes (QR-codes). We have implemented a prototype on Android platforms and evaluated its performance with systems metrics and subjective...
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