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Underwater acoustic communications are limited by the following channel impairments: time variability, narrow bandwidth, multipath, frequency selective fading and the Doppler effect. Orthogonal Frequency Division Modulation (OFDM) is recognized as an effective solution to such impairments, especially when optimally designed according to the propagation conditions. On the other hand, OFDM implementation requires accurate channel knowledge atboth transmitter and receiver sides. Long propagation delay may lead to outdated channel information. In this work, we present an adaptive OFDM scheme where channel state information is predicted through a Kalman-like filter so as to optimize communication parameters, including the cyclic prefix length. This mechanism aims to mitigate the variability of channel delay spread. This is cast in a protocol where channel estimation/prediction are jointly considered, so as to allow efficiency. The performance obtained through extensive simulations using real channels and interference show the effectiveness of the proposed scheme, both in terms of rate and reliability, at the expense of an increasing complexity. However, this solution is significantly preferable to the conventional mechanism, where channel estimation is performed only at the receiver, with channel coefficients sent back to the transmit node by means of frequent overhead signaling.

In this paper, we address the problem of green Compressed Sensing (CS) reconstruction within Internet of Things (IoT) networks, both in terms of computing architecture and reconstruction algorithms. The approach is novel since, unlike most of the literature dealing with energy efficient gathering of the CS measurements, we focus on the energy efficiency of the signal reconstruction stage given the CS measurements. As a first novel contribution, we present an analysis of the energy consumption within the IoT network under two computing architectures. In the first one, reconstruction takes place within the IoT network and the reconstructed data are encoded and transmitted out of the IoT network, in the second one, all the CS measurements are forwarded to off-network devices for reconstruction and storage, i.e., reconstruction is off-loaded. Our analysis shows that the two architectures significantly differ in terms of consumed energy, and it outlines a theoretically motivated criterion to select a green CS reconstruction computing architecture. Specifically, we present a suitable decision function to determine which architecture outperforms the other in terms of energy efficiency. The presented decision function depends on a few IoT network features, such as the network size, the sink connectivity, and other systems&rsquo, parameters. As a second novel contribution, we show how to overcome classical performance comparison of different CS reconstruction algorithms usually carried out w.r.t. the achieved accuracy. Specifically, we consider the consumed energy and analyze the energy vs. accuracy trade-off. The herein presented approach, jointly considering signal processing and IoT network issues, is a relevant contribution for designing green compressive sampling architectures in IoT networks.

In this work, we propose a novel visible light communication (VLC) scheme utilizing multiple different red green and blue triplets each with a different emission spectrum of red, green and blue for mitigating the effect of interference due to different colors using spatial multiplexing. On-off keying modulation is considered and its effect on light emission in terms of flickering, dimming and color rendering is discussed so as to demonstrate how metameric properties have been considered. At the receiver, multiple photodiodes with color filter-tuned on each transmit light emitting diode (LED) are employed. Three different detection mechanisms of color zero forcing, minimum mean square error estimation and minimum mean square error equalization are then proposed. The system performance of the proposed scheme is evaluated both with computer simulations and tests with an Arduino board implementation.

Cognitive radio (CR) is currently one of the most promising solutions for designing spectrum-efficient wireless com- munication systems. In this paper, we present a greedy cognitive access policy that handles spectrum sensing with the tools of image processing. By means of the Wigner-Ville transform (WVT), we are able to analyze the time and frequency features of the received interference, and represent them on a time-frequency grid as an image in which brightness reveals the spectrum occupancy. Ac- cording to sensed interference, each secondary user autonomously tries to access the grid following a multiple-division principle, i.e., by properly shaping the signal in the code, time, and frequency domains. In detail, this is realized by processing the WVT to derive the shaping mask (and the matching algorithm) that allows the filling up of the "time spectrum holes." Numerical simulations and a test-bed implementation show how the proposed scheme outper- forms selected state-of-the-art approaches while still presenting an affordable computational cost. Index Terms—Cognitive radio (CR), edge detection (ED), multiple access, Wigner-Ville transform (WVT). I. INTRODUCTION developed here fully embraces the cognitive paradigm and, following (3), is characterized by awareness (through interfer- ence shape detection), the ability to make decisions (shaping is based on the learning/acquisition phases), adaptivity (to con- dition evolutions), reliability (i.e., robustness to impairments), and efficiency (from smart energy consumption). A possible application of this kind of device ranges from medical body area networks (MBANs) or smart grids (not power-lined) to public safety networks. Establishing a connection easily is the common denominator of these networks. In fact, smart grids allow the connection of new devices in an unlicensed band (e.g., electrical vehicles needing to be charged). In the area of public safety, CR was identified in 2008 by both a National Emergency Communications Plan report and the National Broadband Plan (4) as one of the emerging technologies for increasing effi- ciency and effectiveness of spectrum usage. Finally, MBANs need devices able to work in some spectrum bands subject to constraints related to forbidden bands, as specified by different hospitals. In this regard, flexibility and self-configuring ability are two relevant issues. The proposed approach answers those requests.

The boost of signal processing on graph has recently solicited research on the problem of identifying (learning) the graph underlying the observed signal values according to given criteria, such as graph smoothness or graph sparsity. This paper proposes a procedure for learning the adjacency matrix of a graph providing support to a set of irregularly sampled image values. Our approach to the graph adjacency matrix learning takes into account both the image luminance and the spatial samples' distances, and leads to a flexible and computationally light parametric procedure. We show that, under mild conditions, the proposed procedure identifies a near optimal graph for Markovian fields; specifically, the links identified by the learning procedure minimize the potential energy of the Markov random field for the signal samples under concern. We also show, by numerical simulations, that the learned adjacency matrix leads to a higly compact spectral wavelet graph transform of the so obtained signal on graph and favourably compares to state-of-the-art graph learning procedures, definetly matching the intrinsic signal structure.

The aim of this work is the development of a steganographic technique for the MP3 audio format, which is based on the Peak Shaped Model algorithm used for JPEG images. The proposed method relies on the statistical properties of MP3 samples, which are compressed by a Modified Discrete Cosine Transform (MDCT). After the conversion of MP3, it’s possible to hide some secret information by replacing the least significant bit of the MDCT coefficients. Those coefficients are chosen according to the statistical relevance of each coefficient within the distribution. The performance analysis has been made by calculating three steganographic parameters: the Embedding Capacity, the Embedding Efficiency and the PSNR. It has been also simulated an attack with the Chi-Square test and the results have been used to plot the ROC curve, in order to calculate the error probability. Performances have been compared with performances of other existing techniques, showing interesting results.

On field monitoring of athlete performance is a growing area of interest in elite, professional and even some amateur sports. Metrics routinely monitored can be tactical, physiological and biomechanical, some methods are more labor intensive than others such as bloods and video coded and hand scored performance data. More recently the introduction of wearable sensors and GPS have allowed comparatively large amounts of data to be collected. These sensors are changing the way athletes are assessed, and today are routinely used by a number of professional football codes. Near real time systems, have been shown to enable the information to be accessed more quickly and thus the data can be used tactically, for workload management during game play, in addition to post game analysis. One of the major challenges is to have robust wireless network solutions for this challenging environment. This paper implements a number of player based network topologies and protocols in a simulation environment to test various scenarios, as a tool for future development. Performance limitations to throughput and goodput are used to identify potential bottlenecks. Because the construction of physical hardware devices for athletes and networks, simulation is an attractive process that can shorten development time, identify and solve design problems more rapidly. These tests are intended as an input to designing better devices, networks and thus optimizing ambulatory systems for range, battery life and size reduction. © 2013 Published by Elsevier Ltd. Selection and peer-review under responsibility of RMIT University

Ports are opened infrastructures whose security is infl uenced by a plenty of parameters such as people/ vehicle fl ows. The movement of these fl ows must be accurately checked and controlled to ensure a correct management of security. In ports characterized by high fl ows, the security management must unavoidably use integrated access control systems that ensure a proper organization of the fl ows themselves. The present paper illustrates the work made to design and realize the integrated access control system of the most important commercial and tourist ports of Italy. Since the core of the access control system is represented by a server farm that must operate with a high effi ciency, to guarantee a fast response to the high fl ows of people and vehicles, the system is endowed with a loading balance mechanism of server farm itself, based on genetic controller, that ensures optimal operative velocities and performances, as demonstrated in the paper.

Wireless networks are very useful in mobile services. In particular environments, such as the underground Gran Sasso mountain National Laboratories of the Italian Institute of Nuclear Physics they represent a vital resource for safety/security/communication. The purpose of this paper is to illustrate the design procedure, based on genetic algorithm, which has been used to design the mentioned wireless network, guaranteeing a high level of performances and reliability. Keywords genetic algorithm, Wireless network design Language: en

A high safety and security level of a complex system is very difficult to be reached, guaranteed, and managed if the system is characterized by a peculiar complexity and physical extension, due to the elevate number of parameters to be checked and controlled. The use of human resources needs an elevate number of personnel members that could not only be able to reach the desired goal but could also be exposed to severe risks in the presence of dangerous and emergency situations. For this reason, it is necessary to use integrated safety/security/communication systems that are capable of managing the elevate number of parameters involved, reducing the number of personnel members, and increasing their functionalities and operability. In this paper the integrated safety/security/communication system of the Gran Sasso Mountain in Italy, characterized by a high and unique complexity from the international point of view, is illustrated. The system is also endowed with an efficient early warning system capable of predicting in advance, with an error equal to zero, any critical situations, allowing the activation of the relative procedures to avoid critical and dangerous situation. Keywords Control system, early warning system, integrated safety/security system, supervision system, telecommunication system Language: en

The aim of this paper is to show the accuracy and time results of a text independent automatic speaker recognition (ASR) system, based on Mel-Frequency Cepstrum Coefficients (MFCC) and Gaussian Mixture Models (GMM), in order to develop a security control access gate. 450 speakers were randomly extracted from the Voxforge.org audio database, their utterances have been improved using spectral subtraction, then MFCC were extracted and these coefficients were statistically analyzed by GMM in order to build each profile. For each speaker two different speech files were used: the first one to build the profile database, the second one to test the system performance. The accuracy achieved by the proposed approach is greater than 96% and the time spent for a single test run, implemented in Matlab language, is about 2 seconds on a common PC.

The realization of security wired network is very critical when the network itself must be installed in an environment full of restrictions and constrains such as historical palaces, characterized by unique architectural features. The purpose of this paper is to illustrate an advanced installation design technique of security wired network based on genetic algorithm optimisation that is capable of ensuring high performances of the network itself and significant reduction of the costs. The same technique can be extended to safety system such as fire signalling.

The purpose of this paper is to solve the problem of Ad Hoc network routing protocol using a Genetic Algorithm based approach. In particular, the greater reliability and efficiency, in term of duration of communication paths, due to the

Monitoring network performance and status is a fundamental task for network operators as it directly impacts the quality of the offered services and hence user satisfaction. For this purpose a consolidated approach, which is largely adopted by network operators, is based on the so-called KPIs (key performance indicators). In this paper, we propose and discuss a set of KPIs to monitor network performance of the new HSDPA enhanced UMTS infrastructure. KPI statistics are collected and analysed from the novel HSDPA network of H3G, one of the major Italian mobile network operators.

Cox and Griffiths define as psychosocial risks at work “those aspects of the planning, organization and management of work, which, along with their environmental and social contexts, may affect mental and physical health of the employees, directly or indirectly producing stress”. Therefore, a more effective approach to occupational safety and security should include integrated risk management through the identification of any work stress related problem. The purpose of this paper is to analyze the possible correlation of risk at work with the modification of sleep, and inside it, the specific function of dream activity.

Iris recognition is regarded as the most reliable and accurate biometric identification system available. The present work involves the development of a novel technique in order to improve the performance of iris recognition systems. We have used for our experiments a publicly available iris recognition system. Tests on CASIAv3 image database have resulted in a 2% accuracy improvement with respect to traditional methods; a significant one in iris recognition.

We propose a vsible light communication scheme utilizing red, green and blue light-emitting diodes (LEDs) and three color-tuned photodiodes. Amplitude shift keying modulation is considered, and its effect on light emission in terms of flickering, dimming, and color rendering is discussed. The presence of interference at each photodiode generated by the other two colors is used to improve detection since interference is symbol-dependent. Moreover, the capability of the photodiodes to follow the LEDs speed is considered by analyzing the possibility of equalizing the received signal, and also self-interference mitigation is proposed. The system performance is evaluated both with computer simulations and tests on an Arduino board implementation.

Choosing or switching between heterogeneous networks according to the highest performance in terms of quality of service is largely inefficient in vertical handover. In fact a service may have unstable performance and require highly frequent vertical handover procedures. In this paper we consider the impact of statistical fluctuations of performance parameters (decision under risk) and propose a soft algorithm that exploits the statistical knowledge in order to reduce outage probability.

The need for underwater reliable connections requested to provide different services as sea monitoring, devices control and camera images/videos may lead to require also large rate values. Due to the very limited bandwidth achieving few Khz, space diversity techniques can aid in this twofold mission. In this paper we investigate the use of an underwater acoustic MIMO technique, and jointly adopt the Pulse Position Modulation (PPM), in order to improve the data rates without reducing the reliability of the link. PPM is known to be power efficient modulation format while it is bandwidth inefficient so the use of MIMO can compensate that drawback with reasonable complexity. The performance has been evaluated on the basis of signal recordings for what concerns interference.

The effectiveness of the adaptive maximum a posteriori (MAP) receiver in Cusani and Mattila is verified for digital HF links between mobile and/or fixed units. Following Cusani and Mattila (1998), a suitable MAP algorithm is employed to compute symbol-by-symbol (SBS) the a posteriori probabilities (APPs) of the channel state; from these, the detected data stream is obtained. The same APPs are employed by an adaptive nonlinear Kalman-like filter to estimate recursively the time-varying channel with fast convergence and good tracking properties, overcoming the delay problem suffered by conventional adaptive MLSE-VA detectors. Computer simulations allow to compare the adaptive SBS-MAP with other receivers (DFE, MLSE) and verify its effectiveness in the HF environment.

Dual-polarized signaling constitutes an effective frequency-reuse technique to enhance the cell capacity in cellular mobile-radio systems. In the present paper, we present a new cross-polarization interference canceler (XPIC) which accomplishes the polarization-recovery task in time-division multiple-access (TDMA)-based cellular radio systems. The main new attractive feature of the proposed XPIC is that it is able to work even in the presence of unknown and possibly time-variant random phase fluctuations, as those due to imperfect phase recovery at the receiver side.

In this paper we investigate how to rephrase the concepts of cognitive access, originally developed for radio communications, in the framework of underwater acoustic communications. Differently from classical cognitive radio access, where each signal at the receiver is generated by a communication source, in the underwater scenario acoustic signals at the general receive node are likely to be due to communication source as well as natural/artificial acoustic sources (e.g mammals, ship engines and so forth). In order to maximize the access probability for cognitive acoustic nodes, we then focus on understanding the nature of the sensed interference via the tools of image classification, being the image the spectrogram of the acquired signal.

This paper addresses the problem of texture images recovery from compressively sampled measurements. Texture images hardly present a sparse, or even compressible, representation in transformed domains (e.g. wavelet) and are therefore difficult to deal with in the Compressive Sampling (CS) framework. Herein, we resort to the recently defined Graph-based transform (GBT), formerly introduced for depth map coding, as a sparsifying transform for classes of textures sharing the similar spatial patterns. Since GBT proves to be a good candidate for compact representation of some classes of texture, we leverage it for CS texture recovery. To this aim, we resort to a modified version of a state-of-the-art recovery algorithm to reconstruct the texture representation in the GBT domain. Numerical simulation results show that this approach outperforms state-of-the-art CS recovery algorithms on texture images.

The passive radar uses opportunistic illuminators, such as FM radio or TV transmitters, cellular telephone base stations, etc., to detect and track moving targets. Due to the fact that the radar itself does not transmit any power, it is undetectable. The other advantages of passive radar include its low power consumption, low cost and potential ability to detect stealth targets, due to the multistatic geometry and low frequencies used as weel as, it reduces electromagnetic pollution. This paper tackles with the problem of detecting targets close to the coastal and present on the sea surface by using opportunistic signals as The receiving operations aim at detecting the possible presence of reflective objects by stressing the diversity properties of the multiple-input multiple-output configuration due to multiple transmissions related to different communication services.

New analytical upper bounds are derived for the performance of symbol-by-symbol maximum-likelihood (ML) Abend-Fritchman-type detectors for multi-amplitude/phase-modulated digital sequences transmitted over time-dispersive (generally) time-variant linear channels introducing finite intersymbol interference (ISI) and additive white Gaussian noise (AWGN). The proposed bounds are obtained starting from a novel form of the standard Bhattacharyya bound and take explicitly into account the allowed decoding delay. Both deterministic and random multipath slow-fading Rayleigh transmission ISI channels are considered. Simulation results obtained for some test channels of practical interest show the tightness of the derived analytical bounds.

A new tight analytical upper bound is presented for the performance of finite-delay symbol-by-symbol (SBS) Abend-Fritchman-like decoding of trellis-encoded data crossing arbitrary (eventually time-varying) discrete memoryless channels (DMCs). On the basis of this bound, a related criterion for the optimal design of trellis codes with SBS decoding is then proposed. It gives rise to an effective procedure for the construction of good trellis codes (generally time varying and nonlinear) with assigned decoding complexity.

Vehicle to Infrastructure (V2I) networks can help managing different on-the-road applications and services, especially where the vehicles population is low and Internet access is needed for messaging, alerts, entertainment. Accessing a network through a proper technology requires the possibility of establishing connections with a minimum quality level; besides, a mechanism for switching from a network with poor performance to a better one by means of a so-called Vertical HandOver (VHO) may result of paramount importance. In this work we propose a switching mechanism based on sensing and processing of some physical/access/networking parameters in order to choose the technologies allowing the minimization of outages.

In the last years biometry has shown a growing interest and it is used in a plenty of applications and devices. The term biometry derives from the Greek term “bios” (life) and “metros” (to measure) and it represents the science that studies the mathematical relations between human behaviors or human physical features. A specific branch of biometrics is represented by human signature recognition that allows to associate each person to his sign. The purpose of this paper is to present an automatic human signature system based on genetic algorithms (GAs).

In compressive sensing, the Restricted Isometry Property is an analytical condition on the measurement matrix that assures reconstruction of a signal which is sparse either in the spatial or in a transformed domain given an undersampled measurements' set. In this paper, we demonstrate the RIP for a sparse, structured measurements matrix, referred to as Radon-like CS matrix. The sparse Radon-Like CS matrix favorably applies to real sensing problems, since it significantly reduces the energy/bandwidth cost of actually collecting each and every sensed values contributing to the CS measurements. Simulation results confirm the feasibility of field reconstruction from undersampled CS measurements set obtained using the Radon-Like CS matrix.

Vehicular Ad hoc NETworks (VANETs) belong to a subcategory of traditional Mobile Ad hoc NETworks (MANETs). The main feature of VANETs is that mobile nodes are vehicles endowed with sophisticated “on-board” equipments, traveling on constrained paths (i.e., roads and lanes), and communicating each other for message exchange via Vehicle-to-Vehicle (V2V) communication protocols, as well as between vehicles and fixed road-side Access Points (i.e., wireless and cellular network infrastructure), in case of Vehicle-to-Infrastructure (V2I) communications [1].

Efficient algorithms for computing the ‘a posteriori’ probabilities (APPs) of discrete-index finite-state hidden Markov sequences are proposed. They are obtained by reducing the APPs computation to the optimal nonlinear minimum mean square error (MMSE) estimation of the noisily observed sequences of the indicator functions associated with the chain states. Following an innovations approach, finite-dimensional and recursive Kalman-like ‘filter’ and ‘smoothers’ for the Markov chain state sequence are thus obtained, and exact expressions of their MSE performance are given. The filtered and smoothed state estimates coincide with the corresponding APP sequences. Finite-dimensional MMSE nonlinear filter and smoothers are also given for the so-called ‘number of jumps’ and for the ‘occupation time’ processes associated with the Markov state sequence.

Parameter identification of multidimensional noncausal Markov random fields is an important paradigm in multidimensional signal processing and modeling, and the solutions to this problem are employed in many areas of image processing. An original procedure for estimating the model parameters of discrete-index 2-D noncausal Gauss-Markov random fields (GMRFs) from noisy observations is proposed, valid for both finite and infinite lattices and for any kind of boundary conditions. Starting from a suitable "local" representation of the GMRF and taking into account the symmetry property of so-called field potentials, a linear equation set relating the model parameters to the 2-D autocorrelation function (known or estimated) of the observed field is derived. Its solution gives the parameter estimates of the GMRF together with the estimate of the (possibly unknown) variance of the observation noise.

UnderWater Acoustic (UWA) channels are narrow bandwidth and typically affected by some interference due to propagation, Doppler effect, noise and possible disturbing signals originated by different acoustic sources. Orthogonal Frequency Division Modulation (OFDM) is an effective answer to such impairments. Resource management in the framework of OFDM usually makes use of channel knowledge without taking care of its cost. This work tackles with the dualism between channel estimation and channel prediction and its impact on adaptive modulation, both from a bandwidth and power point of view also in the presence of acoustic interference. The main result is that adaptivity is worth even if requires some processing both at the transmit and receive sides.

Cognitive access is growing in importance in radio frequency wireless applications for occupying spectrum holes leaved free by licensed and unlicensed primary services. Recently the cognitive paradigm involved underwater communications aspects since this propagation scenario is, generally, rich of acoustic sources. This justifies the curiosity of the scientific community to investigate the possibility of using some of the concept borrowed by the cognitive paradigm. Specifically, we consider an underwater active sensor network where each cognitive node applies a Wigner-Ville image processing based pattern analysis procedure not only for evaluating the presence of interference but also its nature. In fact, if the source of interference is a network node, coexistence issues should be taken into account, while, when the interference source is external (mammals, bubbles or ship engines), in principle the transmission is possible in the interfered bands, provided the presence of the interference does not affect the overall transmission quality.

The purpose of the present work is to find out a new methodology to automatically detect abnormal situations in high risk places through a video surveillance system. The idea is to retrieve true and predicted movement of the people in the scene then, through a classifier, to map out different abnormal situations comparing proper vectors. To reach its purpose, the proposed methodology uses a multidisciplinary approach. Keywords Abnormal activities recognizer, automatic video surveillance, pedestrian tracker Language: en

Wireless sensor networks (WSN), i.e. networks of autonomous, wireless sensing nodes spatially deployed over a geographical area, are often faced with acquisition of spatially sparse fields. In this paper, we present a novel bandwidth/energy efficient CS scheme for acquisition of spatially sparse fields in a WSN. The paper contribution is twofold. Firstly, we introduce a sparse, structured CS matrix and we analytically show that it allows accurate reconstruction of bidimensional spatially sparse signals, such as those occurring in several surveillance application. Secondly, we analytically evaluate the energy and bandwidth consumption of our CS scheme when it is applied to data acquisition in a WSN. Numerical results demonstrate that our CS scheme achieves significant energy and bandwidth savings wrt state-of-the-art approaches when employed for sensing a spatially sparse field by means of a WSN., Comment: Submitted to EURASIP Journal on Advances in Signal Processing

The purpose of this paper is to present an all-optical EXOR for cryptographic application based on spatial soliton beams. The device is based on the propagation and interactions properties of spatial soliton in a Kerr nonlinear material. The interaction force between parallel soliton beam is analyzed from the analytical point of view and an exact solution is presented.

A QAM data transmission system operating over a band-limited simplified three-ray multipath fading channel can be equalized by the constant modulus algorithm. A systematic study of the convergence of this blind equalizer is performed in terms of the channel parameters by adopting an analytical model. The convergence behaviour is expressed in terms of the dispersion pattern of the equalized samples around the true symbols of the constellation.

This paper introduces a compressive sampling (CS) scheme for pulse stream images. We adopt a particular sparse sampling matrix, that we call Radon-like CS matrix. Whilst the Radon transform evaluates projections of a given image along different directions, the Radon-like CS matrix evaluates randomly weighted projections of the image along a few directions. We demonstrate that the such CS measurements are invertible and assess the reconstruction accuracy of CS with the Radonlike sampling matrix by numerical trials. The Radon-like CS performs almost as well as state of the art techniques, with a reduced number of operations. As an application example, we show that, when implemented in a resource limited framework such as a Smart Sensors Grid, the sampling matrix significantly reduces inter-node signaling and then the associated energy consumption.

The security of a port is strongly dependent on the use of integrated access control technology systems. Any weakness of the integrated access control system involves a weakness of the port. For this reason it is necessary to design and realize highly integrated, efficient and reliable access control systems. The authors illustrate the work made to design and realize the integrated access control system of the most important commercial and tourist ports of Italy.

Power Line Communications (PLC) are one of the most recent technologies proposed to allow the InHome Internet access, in competition with different Wireless Standards as Wi-Fi. The advantages offered by PLC deal with network availability since each modem connected to the plug is able, in principle, to access the Internet while in the Wi-Fi scenario, the propagation environment strongly influences the received signal strength and consequently connection performance. The conventional approach followed in planning the physical layer of PLC systems, like for example in HomePlug solution, is based on Orthogonal Frequency Division Multiplexing (OFDM), able to combat the frequency selective nature of the channel frequency response. However, OFDM presents some drawbacks as, for example, Peak to Average Power Ratio (PAPR) and Inter Carrier Interference (ICI) while a different approach based on constrained signal shaping (single carrier) can solve these problems. In this direction, this work shows a frequency shaping approach where the frequency occupancy is minimized through constraints on spectral emission and link quality level.

A high safety and security level of a complex system is very difficult to be reached, guaranteed and managed if the system is characterized by a peculiar complexity and physical extension, due to the elevate number of parameters to be checked and controlled. The use of human resources needs an elevate number of personnel members that could not only be unable to reach the desired goal but could also be exposed to severe risks in the presence of dangerous and emergency situations. For this reason it is necessary to use integrated supervision and control systems that are capable of manage the elevate number of parameters involved, reducing the number of personnel members and increasing their functionalities and operability. In this paper the integrated safety/security system of the Gran Sasso mountain (Italy), characterized by a high and unique complexity from the international point of view, is illustrated.

The security of a complex site is strongly dependent on the use of integrated technological systems. Any weakness of the integrated system involves a weakness of the security of the site itself. For this reason it is necessary to design and realize highly integrated, efficient and reliable security systems. The authors illustrate the work made to design and realize the integrated security system of the Senate of the Italian Republic. Keywords communication system, control system, integrated security system Language: en

This paper presents a study for finding a solution to the placement of territorial resources for multipurpose wireless services considering also the restrictions imposed by the orography of the territory itself. To solve this problem genetic algorithms are used to identify sites where to place the resources for the optimal coverage of a given area. The used algorithm has demonstrated to be able to find optimal solutions in a variety of considered situations.

Vertical handover (VHO) procedure facilitate service continuity in an heterogeneous wireless scenario under varying network as well as channel conditions. Decision criteria for VHO are, mainly, designed to maximize a combination of network parameters in order to guarantee an acceptable service level and maximize network operators and/our users expectation. The objective of this paper is to formalize the VHO decision criteria as a QoS constrain bound problem and propose two strategies that permits to achieve QoS constrains without wasting resources. The former that minimize the power consumption and the latter that minimize the number of VHO. Numerical results are provided in order to compare the two strategies.

Recent advances in wireless technology and decreasing costs of portable devices strongly contributed to increase the popularity of mobile communications. Wireless communication and device integration have lead to the so-called nomadic computing (or mobile computing) where portable devices (such as laptop and handheld computers) allow users to access Internet and data on their home or work computers from anywhere in the world. Multimedia services requirements nowadays encompass not only large bandwidths, but also on-the-move facilities. Future 4th generation wireless communications systems will provide seamless mobility support to access heterogeneous wired and wireless networks (Makhecha & Wandra, 2009), (Lin et al., 2010). Emerging and pre-existing wireless technologies exhibit different characteristics, access technologies, available services and network performances. For example GSM, UMTS, WLAN and WiMAX have different bandwidth (70 Mbps for WiMAX and 9.6 kbps for GSM), cell diameter ( 50 km in LoS for WiMAX and 100 m for WLAN), or handover latency (3 s for WLAN and 50 μs for WiMAX). The increasing demand for services with high QoS requirements and novel mobility scenarios, like on-the-move business users, home and office networks, on-the-move entertainment, info-mobility etc., provide users to be connected to the Internet anytime and anywhere, as well as user services and connectivity be maintained, and kept alive. Mobility management in heterogeneous networks is the essential support for roaming nomadic devices switching from one access technology to another, at the same time maintaining seamless connectivity at high QoS services (i.e. video-streaming). New emerging multimode mobile devices are equipped with multiple wireless network interface cards, providing Vertical Handover capability to autonomously select the best access network. The design of innovative handover mechanisms —sometimes called as handoff— between heterogeneous mobile devices (e.g. PDA, laptop, smart phones) and seamless integration of different integrated network (e.g. GSM, UMTS, HSDPA, GPS, WLAN, Bluetooth and so on) is an open research issue.