Wireless Devices

Nowadays, the use of mobile applications and terminals faces fundamental challenges related to energy constraint. This is due to the limited battery lifetime as compared to the increasing hardware evolution. Video streaming is one of the most energy consuming applications in a mobile system because of its intensive use of bandwidth, memory and processing power. In this work, we aim to propose a methodology for building and validating a high level global power consumption model including a hardware and software elements. Our approach is based on exploiting the interactions between power consumption sub-models of standalone systems in the perspective to build more accurate global model. The interactions are studied within the exclusive context of video streaming applications that are one of the most used mobile applications.

In the traditional IEEE 802.11 wireless LAN using infrastructure mode, all users share the same channel and all packets are forwarded by an access point (AP). As a result, as the number of users in the cell increases, the throughput for each user degrades substantially. If there are users communicating with each other within the cell (as in conferencing or file exchange applications), such throughput degradation could be relieved by making these users communicate through ad hoc connections without going through the AP. The advantages are multi-fold. First, the traffic load at the AP is reduced, hence relieving the contention. Second, ad hoc connections are single-hop, hence improving the channel efficiency. Moreover, ad hoc connections could use different channels, hence multiplying the system bandwidth. In this paper, we propose to integrate the infrastructure mode and the ad hoc mode in a wireless network so as to achieve these advantages. We present a framework for such mixed-mode wireless LAN (termed M 2 -WLAN). In such a network, a node can dynamically switch between the infrastructure mode and the ad hoc mode according to the instruction of the AP, and hence the switching is transparent to the users. Using simulations, we show that M 2 -WLAN can indeed improve system throughput substantially without user's manual configuration.

Automatic optimization of application-specific instruction-set processor (ASIP) architectures mostly focuses on the internal memory hierarchy design, or the extension of reduced instruction-set architectures with complex custom operations. This paper focuses on very long instruction word (VLIW) architectures and, more specifically, on automating the selection of an application specific VLIW issue-width. The issuewidth selection strongly influences all the important processor properties (e.g. processing speed, silicon area, and power consumption). Therefore, an accurate and efficient issue-width estimation and optimization are some of the most important aspects of VLIW ASIP design. In this paper, we first compare different methods for the estimation of required the issue-width, and subsequently introduce a new force-based parallelism estimation method which is capable of estimating the required issue-width with only 3% error on average. Furthermore, we present and compare two techniques for estimating the required issue-width of software pipelined loop kernels and show that a simple utilization-based measure provides an error margin of less than 1% on average.

Among the large number of contributions concerning the localization techniques for wireless sensor networks (WSNs), there is still no simple, energy and cost efficient solution suitable in outdoor scenarios. In this paper, a technique based on antenna arrays and angle-ofarrival (AoA) measurements is carefully discussed. While the AoA algorithms are rarely considered for WSNs due to the large dimensions of directional antennas, some system configurations are investigated that can be easily incorporated in pocket-size wireless devices. A heuristic weighting function that enables decreasing the location errors is introduced. Also, the detailed performance analysis of the presented system is provided. The localization accuracy is validated through realistic Monte-Carlo simulations that take into account the specificity of propagation conditions in WSNs as well as the radio noise effects. Finally, trade-offs between the accuracy, localization time and the number of anchors in a network are addressed.

Le projet TeleResp (2007TeleResp ( -2011)), réalisé dans le cadre de l'appel ANR-TecSan 2007, a été conduit par la société RBI en partenariat avec l'hôpital Raymond-Poincaré de Garches et le CHU de Grenoble. L'objectif principal de ce projet est de développer un outil de mesure et d'acquisition sans fil des signaux respiratoires (mesurés par pléthysmographie par inductance), d'oxymétrie, de position du sujet, de pression buccale et de mouvements des membres. Les champs d'application prévus dans le cadre de ce projet sont l'utilisation à domicile du matériel, d'une part, pour le monitorage de la respiration chez des patients atteints de pathologies neuromusculaires nécessitant une ventilation mécanique et, d'autre part, pour le diagnostic du syndrome d'apnée du sommeil. L'originalité de ce projet réside dans la réalisation d'un matériel utilisable à domicile, dans le milieu habituel du patient en évitant des contraintes de port d'appareils de mesure. Ce nouveau système est évalué, puis validé par les deux centres d'études cliniques. L'ambition de ce projet est de proposer des logiciels d'aide au diagnostic dont la conception a nécessité des travaux de recherches sur la justesse des signaux transmis, la fusion des données issues des capteurs et l'identification des données pertinentes. Répondant à une forte demande du marché, l'enjeu majeur du projet TeleResp est le déploiement industriel, la commercialisation d'un dispositif médical non invasif, autonome et novateur dans la surveillance et le diagnostic de troubles respiratoires, plus particulièrement au cours du sommeil, qui constituent un réel problème de santé publique.

This paper presents an experimental study on the spectrum coexistence 1 problems between multi-radio platforms in dense-radio physical world environments. Computing and communication devices such as laptops and cellular phones with multiple radios including WiFi, Bluetooth, UWB, WiMax and Zigbee in a small conference room face significant interference problems. A realistic small office/home office (SOHO) scenario with ~10-25 multi-radio platforms is mapped onto the ORBIT radio grid testbed, and system throughput results are obtained experimentally, demonstrating significant degradation due to inter-platform interference. The CSCC (Common Spectrum Coordination Channel) protocol proposed in earlier work is used as the basis for implementing a set of distributed spectrum coexistence algorithms intended to improve system performance. Detailed results from ORBIT testbed experiments are given for the proposed CSCC-based distributed spectrum coordination algorithms. The results show significant performance gains due to CSCC coordination, typically achieving ~2x improvement in system throughput for WiFi/Bluetooth dual radio scenarios.

The broadband fixed wireless access systems will be subject to an increasing development during the next 3,ears; these systems will allow to offer the subscriber a full set of services, from the conventional narrow band applications up to the emergent broadband services like Internet access, or leased lines. This rapid growth has carried several initiatives in the telecommunications standardisation bodies, like ETSl in Europe, IEEE in North America, or ITU at international level. These initiatives resulted in the creation of ad hoc groups, for instance the B~x/Hiperaccess project Of ETSh the IEEE 802.16, or the JRG 8A-9B in ITU standards resulting from this activity are expected in 2000/2001. In parallel to this standardisation activity it appeared necessary, to designate, or at least to recommend, dedicated frequency bands for fixed wireless access (FWA) or multimedia wireless systems (MWS) applications. In order to satisfy this need the regulation authorities, especially the CEPT in Europe, are preparing decisions and recommendations which are expected to favour a certain level of harmonisation in the use of the spectrum by FWA or MWS systems.

Leadership within scientific community 9.1.1. Editorial activities 9.1.2. Participation in technical program committees 9.1.3. Conferences, meetings and tutorial organization 9.1.4. Participation in thesis committees 9.1.5. PhD theses defended in 2006 9.1.6. Research administration 9.1.7. Miscellaneous 9.2. Teaching 9.3. Participation in conferences and workshops 10. Bibliography .

The deployment of wireless ad hoc networks faces severe limitations by mutual interference between wireless devices. In this work, we introduce a method to alleviate interference using a medium access control (MAC) layer exploiting multiuser detection (MUD). Instead of interference avoidance, the primary task of such a MAC layer is interference handling. To this end, we first identify link layer requirements for deploying MUD in a decentralized and self-organizing network. Based on these requirements, we propose a MAC protocol supporting MUD. We estimate possible throughput gains of this protocol. Network simulations confirm the analytical results and show remarkable throughput improvements.

The internetwork system between Future IP Networks and ZigBee Wireless Networks has two main approaches; the SIP Proxy Based approach, and the ZigBee Stack Based approach. Because of the dynamic nature of the ZigBee devices, both approaches need to be improved to support the connectivity system and the Quality of Service (QoS) for different types of sensing and actuating applications. This paper proposes an initial design for a modified version of SIP (Mod-SIP) for ZigBee Stack Based approach. In addition, the paper introduces the Combined Approach which is an enhanced internetwork system used to provide more reliable and flexible connectivity system between ZigBee WPANs, and the IP clouds. An initial design and simulation efforts on OPNET implemented to study the current approaches and compare it with the proposed approaches. It shows that the SIP Proxy Based approach is not efficient for Future IP Networks applications as it has a high rate of End-to-End delays because of the lack of flexibility between SIP signaling system and the ZigBee WPANs. The initial investigations shown that the Combined approach can provide more reliable connectivity system with the support for the QoS for different types of instantaneous applications such as VoIP and video conferencing.

Energy is a fundamental resource limitation in mobile and wireless devices. A great deal of research in mobile and wireless networking over the past decade has examined ways of reducing energy usage, including specific techniques such as energy-aware protocols for routing and communication. However, to our knowledge, no systematic way has been developed for reasoning generally about the energy consumption of algorithms. Techniques to understand and reason about the time and space complexity of algorithms, in particular asymptotic analysis and the big-Oh notation, have helped place computer programming as well as system design on a firm theoretical and practical footing. Clearly a method for analyzing energy complexity at the same abstract algorithmic level would be invaluable. However, it is not clear that a uniform abstract model of energy complexity can be developed that is both theoretically tractable and has practical predictive ability. Minimizing energy consumption requires making tradeoffs between many resources, including computation, communication, and memory accesses; taking any single resource as a proxy for energy cost neglects these tradeoffs and may lead to a poor model. In this paper we survey techniques for modeling and minimizing energy consumption at various system levels, so as to place algorithmic energy complexity in perspective. We then discuss the attributes that a model of energy complexity should have, and describe our initial approach towards developing such a model. We end by discussing future technical directions. R. Jain and Z. Ramzan are with DoCoMo Communications Laboratories, USA, Inc.

This report provides a comprehensive profile of Dr. Vasileios Papamichail, a distinguished Electrical and Computer Engineer. His academic journey, rooted at the University of Patras, has fostered a deep specialization in wireless communication systems, with a particular focus on multi-port antenna design, Multiple-Input Multiple-Output (MIMO) systems, and diversity techniques. Currently operating as an independent researcher and the President and CEO of Wi.S.Per. (Wireless System Performance), Dr. Papamichail has made significant contributions to the field through his extensive publications. His pioneering work encompasses advanced simulation methods for wireless systems, novel antenna designs, and sophisticated capacity evaluation techniques. Notably, his recent research explores the interplay between radiation entropy and wireless capacity, aiming to redefine spectral efficiency for next-generation networks. This report exclusively details the professional and academic contributions of the Vasileios Papamichail whose primary expertise is in wireless communications and antenna systems, distinguishing him from other individuals with similar names found in the research material who specialize in fields such as public health, plasma physics, or general business leadership. Dr. Vasileios Papamichail is a prominent Electrical and Computer Engineer whose work has significantly advanced the understanding and performance of wireless communication systems. His expertise is primarily centered on the intricate aspects of multi-element antenna design, their integration into user equipment, and the characterization of wireless channels. His academic and professional trajectory consistently reflects a dedication to pushing the boundaries of wireless technology. It is important to clarify that this report focuses exclusively on the Vasileios Papamichail who is an Electrical and Computer Engineer, born in Patras, Greece, and who received his diploma and PhD from the Electrical and Computer Engineering Department at the Polytechnic School of the University of Patras. His core research interests unequivocally lie in electromagnetic-circuit modeling of compact multi-port antenna systems, performance evaluation of MIMO and Diversity user equipment devices, and wireless channel modeling and characterization. This distinction is crucial because the available information includes references to other individuals with similar names involved in disparate fields, such as public health , dentistry , medical research , business consulting in Romania , or even sports. Furthermore, another individual named Vasileios Papamichail, also with an Electrical Engineering background from Patras, is noted for a PhD in Plasma Physics from a French university and holds patents related to computational mechanics and plasma technology. The consistent thematic alignment across the majority of the provided information confirms the focus of this profile on the wireless communications and antenna systems expert. The need for such careful disambiguation underscores a common challenge in profiling individuals with common names, particularly in academic and professional contexts where multiple experts might share identical or similar

We illustrate the use of the reverberation chamber to simulate fixed wireless propagation environments including effects such as narrowband fading and Doppler spread. These effects have a strong impact on the quality of the wireless channel and the ability of a receiver to decode a digitally modulated signal. Different channel characteristics such as power delay profile and RMS delay spread are varied inside the chamber by incorporating various amounts of absorbing material. In order to illustrate the impact of the chamber configuration on the quality of a wireless communication channel, bit error rate measurements are performed inside the reverberation chamber for different loadings, symbol rates, and paddle speeds; the results are discussed. Measured results acquired inside a chamber are compared with those obtained both in an actual industrial environment and in an office.

Multipath propagation environment effects, such as frequency-selective fading, have a strong impact on the quality of a wireless channel. For example, multipath can impact bit error rate (BER) differently from Gaussian noise. For testing wireless devices/systems in these multipath environments it is imperative to have a reliable, controllable, and statistically repeatable measurement facility. The purpose of this paper is to illustrate how the reverberation chamber can be used to simulate different multipath propagation environments. Channel characteristics such as power-delay profile, RMS-delay spread, and the Rician K-factor are examined. Results for different chamber configurations (e.g., loading of the chamber, antenna positions, etc.) are compared and their effects discussed. Results achieved inside a chamber are compared with those obtained in an actual industrial environment. 1

The use of GPS for personal location using wireless devices requires satellite signal measurements both outdoors and indoors. In the outdoor environment propagation paths may range from line-of-sight to shaded or blocked. The indoor environment may range from single-floor wooden constructions to high-rise buildings and underground facilities. In this paper, a high-sensitivity receiver which operates in unaided stand-alone mode is tested under a range of shaded and blocked signal environments, ranging from residential outdoor areas to urban canyons and residential houses. The measurement analysis is performed in both the observation and position domains. The results show that the receiver tested is able to yield measurements with C/N 0 degradations in excess of 20 dB-Hz, as compared to line-of-sight measurements. Position results are a function of the geometry of the remaining satellites, which in turn is a function of the environment.

We introduce a weighted traffic equilibrium problem in a non-pivot Hilbert space and prove the equivalence between a weighted Wardrop condition and a variational inequality. As an application we show, using some recent results of the Senseable Laboratory at MIT, how wireless devices can be used to optimize the traffic equilibrium problem.

Reduction of CO2 emissions is a major global environmental issue. Over the past few years, wireless and mobile communications are becoming increasingly popular with consumers. The Most popular kind of wireless access is known as Wireless Mesh Networks (WMNs) that provide wireless connectivity through lot cheaper and more supple backhaul infrastructure relative to wired solutions. Wireless Mesh Network (WMN) is a new emerging technology which has been adopted as the wireless internetworking solution for the near future. Due to higher energy consumption in the information and communication technology (ICT) industries, and which would have an impact on the environment, energy efficiency has become a key factor to evaluate the performance of a communication network. This paper primarily focuses on the classification layer the greatest existing approaches devoted to the conservation of energy. It is also discussing the most interesting works on energy saving in WMNs networks.

In this paper we study the characteristics of search queries submitted from mobile devices using various Yahoo! mobile oneSearch applications during a 2 months period in the second half of 2007, and report the query patterns derived from 20 million English sample queries submitted by users in US, Canada, Europe, and Asia. We examine the query distribution and topical categories the queries belong to in order to find new trends. We compare and contrast the search patterns between US vs international queries, and between queries from various search interfaces (XHTML/WAP, java widgets, and SMS). We also compare our results with previous studies wherever possible, either to confirm previous findings, or to find interesting differences in the query distribution and pattern.

Software components embedded in wireless devices are subject to behavior which cannot be fully and realistically predicted. This calls for a runtime management infrastructure that is able to observe and control the components' states and to make their behaviors explicit, tangible and understandable, in any case and at any time. In this paper, we propose a framework for remotely administrating the functional behavior of software components deployed on wireless nodes. This framework is based on components which are locally managed by internal managers on the wireless side. The controllable nature of components relies on executable UML models that persist at runtime. On the administration side, models are replicated and synchronized with the models that constitute the inner workings of the wireless components.

In ad hoc networks, devices are required to selforganize themselves into a network without previously established infrastructure. The kind of ad hoc network we consider in this paper is made up of a multitude of relatively low mobility, short range, wireless devices, pervasively deployed throughout the environment. One of the most important design criteria for this type of network is energy efficiency. This paper looks at the energy efficiency aspect of the system design. Specifically, this paper looks at the optimum one-hop transmission distance that will minimize the total system energy. The analysis assumes that the individual devices do not have power control, but that the transmission range of all the devices as a group can be varied in the design stage. The results show that the optimum one-hop transmission distance is independent of the physical network topology, the number of transmission sources, and the total transmission distance. It only depends on the propagation environment and the device parameters. With this result, some system design trade offs can be made to minimize the total system energy. We discuss what these parameters are, how they interact with each other, and how they can be used to obtain an energy efficient wireless system. We also discuss the implications this result has for future developments of low bit rate, short range, and highly dense wireless devices for ad hoc networks.

The realisation of ubiquitous in-and out-door location awareness needs the exploration of scaleable hybrid solutions that can utilize existing infrastructures in novel and complimentary ways. Our hybrid solution (BlueStar) incorporates mobile terminals (GSM smart phones) with a two-phase approach to location awareness, using existing infrastructure. The first phase relies on a network based signal measurement (timing advance) and cell id. In the second phase the mobile terminal "sniffs" for the identification of local wireless devices, which act as "beacons", in the environment. The mobile terminal does not connect to the beacons; it simple detects their presence. The aim is to offer a privacy enhanced yet flexible indoor/outdoor location management scheme, which allows for only the end-user to be aware of their fine-grained location data. A working example of our BlueStar system is presented along with a preliminary user study of "InfoHoard" a BlueStar game, in an indoor testing environment.

This study examines how uncertainty about rival firm’s behavior affects the equilibrium and its dynamics under heterogenous competition. A differentiated mixed duopoly is considered in which one firm sets a quantity and the other firm charges a price. It is demonstrated that behavioral uncertainty stabilizes the unstable dynamic process in comparison to behavioral certainty and generates Pareto-improvement in the sense that the firms can earn larger profits.

Localization techniques that allow inferring the location of wireless devices directly from received signals have exposed mobile users to new threats. Adversaries can easily collect required information (such as signal strength) from target users, however, techniques securing location information at the physical layer of the wireless communication systems have not received much attention. In this paper, we propose Phantom , a novel approach to allow mobile devices thwart unauthorized adversary's location tracking by creating forged locations. In particular, Phantom leverages cooperation among multiple mobile devices in close vicinity and utilizes synchronized transmissions among those nodes to obfuscate localization efforts of adversary systems. Through an implementation on software-defined radios (GNU Radios) and extensive simulation with real location traces, we see that Phantom can improve location privacy.

Radio Frequency Identification (RFID)is a device used for the detection of objects such that the data can be monitored at each stage. A RFID device consists of a Tag, a Reader and a Server. The Data read by the Tag device need to be send wirelessly to the reader. During the transmission of Data from Tag to Reader the chances of eavesdropping and various attacks is possible. So here proposed a new technique of providing authentication between Tag and the Reader to prevent from various attacks and the data is send securely.

The ultimate goal of mobile and ubiquitous Internet accessibility is not only the seamless integration of wireless devices with traditional fixed networks but also the dynamic differentiation of the provided levels of Quality of Service (QoS) depending on client characteristics. In this context, the paper presents the provisioning of audio streaming with different QoS levels in the application-level ubiQoS middleware. In particular, it focuses on how ubiQoS manages the QoS over the last segment of the audio distribution path towards Bluetooth clients by allocating different types of Bluetooth communication channels (unicast connection-oriented or broadcast connectionless) depending on the differentiated QoS requirements of different user classes. To this purpose, we have designed and implemented a library that extends the JSR82 standard specification with the support of Active Slave Broadcast, thus simplifying the Java-based management of Bluetooth communications. The reported experimental results show the feasibility of our application-level middleware approach in the challenging case of audio streaming with differentiated QoS to resource-limited Bluetooth devices.

The evaluation and learning of classifiers is of particular importance in several computer security applications such as intrusion detection systems (IDSs), spam filters, and watermarking of documents for fingerprinting or traitor tracing. There are however relevant considerations that are sometimes ignored by researchers that apply machine learning techniques for security related problems. In this work we identify and work on two problems that seem prevalent in security-related applications. The first problem is the usually large class imbalance between normal events and attack events. We address this problem with a unifying view of different proposed metrics, and with the introduction of Bayesian Receiver Operating Characteristic (B-ROC) curves. The second problem to consider is the fact that the classifier or learning rule will be deployed in an adversarial environment. This implies that good performance on average might not be a good performance measure, but rather we look for good performance under the worst type of adversarial attacks. We work on a general methodology that we apply for the design and evaluation of IDSs and Watermarking applications. 1 approaches p 0 . As g decreases, more mass of p * 1 concentrated towards the smaller backoff values.

This paper presents EmailValet, a system that learns users' emailreading preferences on email-capable wireless platforms -specifically, on two-way pagers with small "qwerty" keyboards and an 8-line 30-character display. In use by the authors for about three months, it has gathered data on email-reading preferences over more than 8900 email messages received by the authors during this period. The paper presents results comparing the ability of different learning methods to form models that can predict whether a given message should be forwarded to the user's wireless device. Our results show that the best performance of one method, over a range of established learning methods developed on the information retrieval and machine learning communities, was able to achieve a break-even point of over 53% for one user that had received over 5000 messages. We also find that, in general, all methods are able to achieve better performance than what would be achieved by a baseline of simply forwarding all messages to the wireless device, and that many methods are able to find procedures that, although they forward only a small fraction of the messages that a user would want, achieve 100% precision on those messages that it does actually choose to forward. able to achieve a break-even 1 point of 53%. We also present some more detailed analyses of the various methods, including how different ways of encoding the email for the learner affect learning performance. We conclude the paper with a discussion of future work and final remarks.

New microstrip antenna initiated from the portions of  1st order structures of Sierpinski square geometry is  modeled  in this paper as quasi-fractal device using an FR4 substrate of 4.4 dielectric constant, 1.6 mm thickness and 0.02 loss tangent. The intended microstrip antenna is designed for band frequencies  of 3.5 and 7.8 GHz for WiMAX and metrological satellite applications with a bandwidth of 0.66 and 0.78 GHz for each band respectively. The designed antenna has considerable compact size  that is smaller than many reported fractal and non-fractal antenna structures in the literature. Also, it has interesting return loss and radiation results that can be employed in diverse wireless devices. Measured input reflection coefficient, radiation patterns and gain results have been found in good agreement with those predicted by simulations.

PurposeThe purpose of this paper is to describe common methods for evaluating the performance of wireless devices such as wireless sensors in harsh radio environments.Design/methodology/approachThe paper describes how measurements of real‐world propagation environments can be used to support the evaluation process, then presents representative measurement data from multipath environments where sensor networks are likely to be deployed: a fixed‐infrastructure, process‐control environment (here an oil refinery), and a heavy industrial environment (here an automotive assembly plant).FindingsResults on the characterization of multipath in the propagation channel are summarized and how these results may be used in the performance evaluation of sensor networks is discussed.Originality/valueThe paper describes measurement results from environments where little open‐literature data exists on point‐to‐point propagation, specifically high‐multipath environments. These highly reflective scenar...

We present measurement data to support development of technology and standards for broadband, digitally modulated radio communications used by emergency responders. Measurements were conducted at an oil refinery having extensive outdoor piping and other metal components. This structure represents a class of high-multipath, outdoor propagation environments that includes electrical generation facilities, chemical plants, and other outdoor, heavy industrial environments where reliable emergency responder communications is critical. The measurement results presented here quantify the extent of the multipath, loss, and other propagation effects in such high-multipath outdoor environments.

With the proliferation of wireless devices in recent years, there is a growing need to test the operation and functionality of these various devices in different multipath environments, ranging from line-of-sight environment to a pure Rayleigh environment. In this paper we discuss how a reverberation chamber can be used to simulate a controllable Rician radio environment for the testing of a wireless device. We show that by varying the characteristics of the reverberation chamber and/or the antenna configurations in the chamber, any desired Rician -factor can be obtained. Expressions for the desired -factor as a function of the chamber and antenna characteristics will be presented. Experimental results are presented to illustrate the validity of these expressions, to show how the reverberation chamber can be used to simulate different multipath environments, and to show the realization of a controlled -factor test facility. We present both a one-antenna and a two-antenna test configuration approach.

Nowadays, Multiprocessors Systems on Chip (MPSoC) are increasingly becoming complex to design, test and manufacture and represent an emerging paradigm for developing customized, application specific solutions meeting several constrains as time-to-market, performance and power consumption. Over the chip, we have different subsystems interacting each other, offering high possibility of heterogeneity and thread level parallelism. This has an important impact on the overall performance. One procedure to deal this multiobjective optimization problem is by doing an efficient design space exploration (DSE) to find a trade-off among performance (energy-delay and execution time), and area constrains. The aim of this project is to perform the best methodology by modeling this metrics based on statistic inference techniques in order to reduce the time required to explore the large design space of multiprocessors chips, running a variety of applications. The idea is to create a model using only a subset of the applications and then predict performance, avoiding full simulation. The solution proposed is matched with former results obtained from predictive machine learning techniques (ANN). Design, it implies insensivity to factors that produce variability in the results of the system and even when noise is introduced as consequence of this heterogeneity, the performance of the whole system remains acceptable when some application is running inside the chip. This behavior is highlighted since the DSE performed. I.

GOST 28147-89 is a well-known Russian government encryption standard. Its large key size of 256 bits at a particularly low implementation cost make that it is widely implemented and used . In 2010 GOST was submitted to ISO to become an international standard. GOST was analysed by Schneier, Biham, Biryukov, Dunkelman, Wagner, various Australian, Japanese, and Russian scientists, and all researchers seemed to agree that it looks quite secure. Though the internal structure of GOST seems quite weak compared to DES, and in particular the diffusion is not quite as good, it is always stipulated that this should be compensated by a large number of 32 rounds cf. 8] and by the additional non-linearity and diffusion provided by modular additions . At Crypto 2008 the hash function based on this cipher was broken. Yet as far as traditional encryption applications with keys generated at random are concerned, until 2011 no cryptographically significant attack on GOST was found. In this paper we present several new attacks on full 32-rounds GOST. Our methodology is derived from the idea of conditional algebraic attacks on block ciphers [25, 20] which can be defined as attacks in which the problem of key recovery is written as a problem of solving a large system of algebraic equations, and where the attacker makes some "clever" assumptions on the cipher which lead to an important simplification in the algebraic description of the problem, which makes it solvable in practice if the assumptions hold. Our methods work by black box reduction and allow to literally break the cipher apart into smaller pieces and reduce breaking GOST to a low data complexity software/algebraic/MITM attack on 8 or less rounds. We obtain some 50 distinct attacks faster than brute force on the full 32-round GOST and we provide five nearly practical attacks on two major 128-bit variants of GOST (cf. Table ). Recent updates: Our latest attacks combine all of [higher-order] truncated differentials, complexity reduction, [approximate] fixed points, reflections, MITM and software/algebraic attacks. Single key attacks are summarized in Table p. 53 and Table p. 153 and the fastest of these is a differential attack in 2 179 by Courtois . In the multiple random key scenario the cost of recovering one full 256-bit GOST key decreases in a spectacular way at the expense of further growing data requirements. In Table page 128 we summarize all our attacks in this space. Our fastest attack achieves a nearly feasible T= 2 101 (cf. Section 28.6 and [34]).

Evaluating coexistence between wireless local area networks and wireless personnel area networks is an important issue for determining usage policies for wireless devices that are collocated and sharing the same frequency spectrum. A method is presented for evaluating the impact Bluetooth piconets will have on IEEE 802.11b performance when collocated within a specific building layout. The method is centered on analytically evaluating the probability of collision between an 802.11b packet and packets from Bluetooth piconets. The analytical model is based on a parametric representation of the Bluetooth interference environment and a site specific propagation model used to estimate the received signal powers. I.

Wireless communication has become an important feature for commercial products and a popular research topic within the last ten years. There are now more mobile phone subscriptions than wired-line subscriptions. Lately, one area of commercial interest has ...

The need for mass-produced inexpensive wireless devices operating under strict energy constraints poses new challenges in the system design methodology. This paper presents a methodology for designing wireless nodes in which a low cost, reliable antenna is realized by printed circuit traces. We show how to combine the analysis from 2.5D and 3D EM simulators with the PCB design tools to create predictable nodes with printed antennas that meet stringent power and data transmission range goals. The presented approach is applied to the design of a IEEE802.15.4 wireless node deployed in several indoor environments.

New microstrip antenna initiated from the portions of  1st order structures of Sierpinski square geometry is  modeled  in this paper as quasi-fractal device using an FR4 substrate of 4.4 dielectric constant, 1.6 mm thickness and 0.02 loss tangent. The intended microstrip antenna is designed for band frequencies  of 3.5 and 7.8 GHz for WiMAX and metrological satellite applications with a bandwidth of 0.66 and 0.78 GHz for each band respectively. The designed antenna has considerable compact size  that is smaller than many reported fractal and non-fractal antenna structures in the literature. Also, it has interesting return loss and radiation results that can be employed in diverse wireless devices. Measured input reflection coefficient, radiation patterns and gain results have been found in good agreement with those predicted by simulations.

New printed slot antenna initiated from the portions of 1 st order structures of Sierpinski square geometry is modeled in this paper as a quasi-fractal device using an FR4 substrate of 4.4 dielectric constant, 1.6 mm thickness and 0.02 loss tangent. The intended antenna is designed for band frequencies of 3.5 and 7.8 GHz for WiMAX and metrological satellite applications with a bandwidth of 0.66 and 0.78 GHz for each band respectively. Also, it has interesting return loss and radiation results that can be employed in diverse wireless devices. Measured input reflection coefficient, radiation patterns, and gain results have been found in good agreement with those predicted by simulations.

Energy-efficient design has become increasingly important to battery-powered wireless devices. In this work, we focus on the energy efficiency of a cognitive radio network, in which a secondary user senses the channels licensed to some primary users sequentially before it decides to transmit. Energy is consumed in both the channel sensing and transmission processes. The energy-efficient design calls for a careful design in the sensing-access strategies and the sensing order, with the sensing strategy specifying when to stop sensing and start transmission, the access strategy specifying the power level to be used upon transmission, and the sensing order specifying the sequence of channel sensing. The objective is to identify the sensing-access strategies and the sensing order that achieve the maximum energy efficiency. In this talk, joint design of the channel sensing order and the sensing-access strategies will be presented, together with performance evaluation of the proposed energy-efficient design.

This paper presents a spectrum etiquette protocol for efficient coordination of radio communication devices in unlicensed (e.g. 2.4 GHz ISM and 5 GHz U-NII) frequency bands. The proposed etiquette method enables spectrum coordination between multiple wireless devices using different radio technologies such as IEEE 802.11.x, 802.15.x, Bluetooth, Hiperlan, etc. The basic idea is to standardize a simple common protocol for announcement of radio and service parameters, called the "common spectrum coordination channel (CSCC)". The CSCC mechanism is based on the low bit-rate mode of the 802.11b physical layer, along with a periodic broadcast protocol at the MAC layer. The CSCC protocol is "policy neutral" in the sense that it provides a general mechanism which can accommodate a wide range of specific spectrum sharing rules. One possible CSCC protocol implementation is described in terms of the packet formats used and related channel access rules. Proof-of-concept experimental results from a CSCC prototype are presented for an example scenario in which nearby 802.11b and Bluetooth devices contend for 2.4 GHz ISM band access. Results showing file transfer delay with and without CSCC etiquette are given for comparison purposes.

This paper presents a spectrum etiquette protocol for efficient coordination of radio communication devices in unlicensed (e.g. 2.4 GHz ISM and 5 GHz U-NII) frequency bands. The proposed etiquette method enables spectrum coordination between multiple wireless devices using different radio technologies such as IEEE 802.11.x, 802.15.x, Bluetooth, Hiperlan, etc. The basic idea is to standardize a simple common protocol for announcement of radio and service parameters, called the "common spectrum coordination channel (CSCC)". The CSCC mechanism is based on the low bit-rate mode of the 802.11b physical layer, along with a periodic broadcast protocol at the MAC layer. The CSCC protocol is "policy neutral" in the sense that it provides a general mechanism which can accommodate a wide range of specific spectrum sharing rules. One possible CSCC protocol implementation is described in terms of the packet formats used and related channel access rules. Proof-of-concept experimental results from a CSCC prototype are presented for an example scenario in which nearby 802.11b and Bluetooth devices contend for 2.4 GHz ISM band access. Results showing file transfer delay with and without CSCC etiquette are given for comparison purposes.

Consider a supervised learning problem in which examples contain both numerical-and text-valued features. One common approach to this problem would be to treat the presence or absence of a word as a Boolean feature, which when combined with the other numerical features enables the application of a range of traditional feature-vector-based learning methods. This paper presents an alternative approach, in which numerical features are converted into "bag of word" features, enabling instead the use of a range of existing text-classification methods. Our approach creates a set of bins for each feature into which its observed values can fall. Two tokens are defined for each bin endpoint, representing which side of a bin's endpoint a feature value lies. A numerical feature is then assigned the bag of tokens appropriate for its value. Not only does this approach now make it possible to apply text-classification methods to problems involving both numerical and text-valued features, even problems that contain solely numerical features can be converted using this representation so that text-classification methods can be applied. We therefore evaluate our approach both on a range of real-world datasets taken from the UCI Repository that solely involve numerical features, as well as on additional datasets that contain both numerical-and text-valued features. Our results show that the performance of the text-classification methods using the binning representation often meets or exceeds that of traditional supervised learning methods (C4.5, k-NN, NBC, and Ripper), even on existing numericalfeature-only datasets from the UCI Repository, suggesting that text-classification methods, coupled with binning, can serve as a credible learning approach for traditional supervised learning problems.

This paper describes experiments in using audible sound as a means for wireless device communications. The direct application of standard modulation techniques to sound, without further improvements, results in sounds that are immediately perceived as digital communications and that are fairly aggressive and intrusive. We observe that some parameters of the modulation that have an impact in the data rate, the error probability and the computational overhead at the receiver also have a tremendous impact in the quality of the sound as perceived by humans. This paper focuses on how to vary those parameters in standard modulation techniques such as ASK, FSK and Spread-Spectrum to obtain communication systems in which the messages are musical and other familiar sounds, rather than modem sounds. A prototype called Digital Voices demonstrates the feasibility of this music-based communication technology. Our goal is to lay out the basis of sound design for aerial acoustic communications so that the presence of such communications, though noticeable, is not intrusive and can even be considered as part of musical compositions and sound tracks.