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In this paper, ultra-wideband radio propagation over desktop surface is examined. Two scenarios are considered: first the propagation over a wooden desktop surface and second over the same surface but covered with aluminum foil. The comparisons of path-loss laws and delay-spread characteristics indicate that the introduction of a metal surface could provide a higher transmitter range, i.e. a higher...
In this paper we describe a practical algorithm to generate impulsive noise according to how it appears in the baseband after demodulation in a communication process. This algorithm offers flexibility to vary the parameters that characterize impulsive noise by taking into account former researcher's works. According to it, we also developed a program which generates impulsive noise sequences that...
Impulsive noise (IN) is an electromagnetic impairment that has been proved to be very harmful to Orthogonal Frequency Division Multiplexing (OFDM) radiocommunication systems. In this paper, a novel method for removing IN from OFDM receivers is presented. The method is based in the correlation existing between the horizontal and vertical polarization components of IN, and it is applicable to OFDM systems...
The need of traceability systems adequate for food is a matter of fact: provenance, means of processing, time of the actions, temperature during transportation, are only a few of the possible data a consumer wants to know to buy with confidence. Among the others, the wine sector is especially susceptible of applying such a system: this sector produces highly added value products and the consumers...
The 3GPP has chosen the Session Initiation Protocol as signalling protocol for the IP Multimedia Subsystem; therefore, it is expected that telecom operators will widely use it for their systems. SIP relies on an underlying transport protocol, like, e.g., TCP, UDP or SCTP. In the case of UDP, SIP has to ensure itself that messages will be reliably delivered. For this purpose, retransmission timers...
RFID systems are complex heterogeneous systems, consisting of analog and digital hardware components (readers and tags) and software components (middlewares and ERP applications). In addition to these complexity and heterogeneity, RFID systems rely on low cost tags and are often used in harsh environments. As a consequence, they do not always ensure robust communications (i.e. tag detection). Thus,...
Waveforms acquired from a power plant were analyzed with the Discrete Wavelet Transform (DWT). For the steady state case reference data were calculated (details and approximations vectors and 3-D tables which can be used to determine faster, in an original way, the parameters of a harmonic distortion). An original algorithm for the evaluation of parameters corresponding to harmonic disturbances was...
LepidaTV is a regional digital channel, born for providing citizens various services of the Public Administration, that are already available using different communication media, internet for example, through television too, taking advantage of the transition from analog to digital. In this paper we will describe a new service that has been recently full-finished and is now broadcasted on LepidaTV:...
We address a simple protocol that can be used to distribute a shared key to three or more users over an insecure channel. We use the Elgamal protocol to set up the system and we define a generalization of Massey Omura protocol to allow one user to send a message or a shared key to a group of users. Moreover we analyse some problems about the decryption shared key of Massey Omura generalized protocol...
In this paper, we consider cell selection to maximize the expected capacity in heterogeneous cellular networks where a number of femtocells operate in the macrocell. Conventional cell selection schemes based on the received signal strength or the signal-to-interference plus noise power ratio may not maximize the ergodic capacity because the operation condition of macrocell and femtocell can be different...
Electromagnetic modeling of large scale problems arising from complex geometries, such as the human body or the specific organ, is generally undertaken by numerical methods implemented in simulation software packages. The structures involving high discretization density (mainly based on MRI images and handled by FDTD method) consume tremendously high computational cost. On the other hand, oversimplified...
To achieve availability and reliability, distributing data over several nodes within a network is widely used today. But distributing data to all nodes within a network becomes complicated if data should stay consistent while all of the nodes are allowed to insert, update or delete data. Common approaches focus on solutions where applications rely on replication algorithms and mechanisms provided...
Wireless communication with simple decoder leads to less power consumption in receivers. Based on this, a family of space-time block codes, called T-codes, has been recently proposed. This family benefits from simple decoder for zero-forcing (ZF) receiver. Focusing on ZF receivers, in this paper, we modify the performance of T-code family without sacrificing the simplicity of the receiver. We suggest...
Most contemporary embedded devices, such as wireless routers, digital cameras, and digital photo frames, have Web based management interfaces that allow an administrator to perform management tasks on the device from a Web browser connecting to the device's Web server. It has been shown earlier that many of these devices are vulnerable to Cross Site Scripting type attacks whereby some malicious JavaScript...
A very promising application of Ultra Wide-Band radar technology is the continuous monitoring of some physiological parameters, like those relevant to the breath and heartbeat activity, without the need of any invasive tool neither of any contact with the subject under analysis. This idea has already appeared in the literature since some time, but its practical feasibility and assessment is still...
The paper deals with an assessment of transient impedance of the grounding electrode. The mathematical model is based on the thin wire antenna theory and related Pocklington integro-differential equation in the frequency domain, which is numerically treated via Galerkin-Bubnov variant of indirect Boundary Element Method (GB-IBEM). Two different approaches for transient impedance are discussed in detail...
Lightning electromagnetic field results are presented in this paper for negative discharges of the first return strokes into a perfectly conducting ground. For such strokes multi-peaked channel-base currents are experimentally measured usually having two emphasized peaks. If a new double-peaked function is chosen to approximate such a channel-base current then lightning electromagnetic field waveshapes...
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