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Contradictory to communication safety in the aviation field communication security has received relatively little attention to date, although the threats regarding air traffic security have been rapidly increasing in recent years. Within the project GAMMA (Global ATM Security Management) the German Aerospace Center (DLR) is developing a prototype to support air traffic controllers (ATCO) in detecting intrusions into the air ground voice system and therefore allow subsequent mitigating actions to be conducted.

Artículo que trata de cómo construir una herramienta de enseñanza basada en receptores de radio definidos por software., En este artículo se presenta un equipo electrónico para investigación y enseñanza desarrollado y patentado por investigadores del Grupo Señales, Sistemas y Comunicaciones Navales con el fin de proporcionar a los alumnos del Grado de Ingeniería Radioelectrónica una plataforma de ensayo en la que afianzar sus conocimientos, mediante prácticas regladas o prácticas sugeridas a iniciativa de los propios alumnos, o desarrollar sus Proyectos de Fin de Grado, Máster e incluso Tesis Doctorales. Estos instrumentos electrónicos, que normalmente son receptores de radiofrecuencia adaptados a sistemas computerizados de presentación en pantalla, representan un alto coste de adquisición y mantenimiento y son impensables en talleres de enseñanza de una pequeña Universidad Pública, lo que obliga a agudizar el ingenio del profesorado con el fin de conseguir la mejor preparación técnica, teórica y práctica, de su alumnado mediante plataformas de bajo coste. La experiencia de este Grupo de Investigación, ya demostrada desde 2012 mediante el Demostrador de Conceptos Marconi (http://marconi.uca.es)[1], ha permitido diseñar un sistema de frecuencias superiores en el cual se adaptan los dispositivos RTL-SDR a antenas servocontroladas en las bandas de VHF, UHF y SHF, siendo posible aplicar el nuevo demostrador a casi todas las asignaturas “de Radio”., Grupo Señales, Sistemas y Comunicaciones Navales. Universidad de Cádiz III Congreso Nacional de I+D en Defensa y Seguridad, 2015

VHF står för "Very High Frequency" och är ett frekvensband som ligger i området 30 - 300 MHz. Maritim VHF är standard för Sjöfartsverket och fungerar över hela världen. Det är ett kommunikationssystem som bidrar till ökad säkerhet och kan rädda liv på sjön. Andra vanliga kommunikationssystem som mobiltelefoni fungerar inte tillförlitligt. Idag fungerar mobiltelefoni i stora delar av skärgården och längs kusterna men när det gäller kommunikation mellan fartyg längre ut till havs är den maritima VHF-kommunikationen överlägsen. Sjöfartsverket driver för sitt eget och kunders behov ett mobilradionätverk kallat kustradionätverket. Radiotrafiken i nätet sker både på Very High Frequency (VHF) och Medium frequency (MF). VHF-systemet är ett internationellt system som bland annat används till att kommunicera till sjöss och den trafiken befinner sig i frekvensbandet 155.5 - 162.025 MHz. Inom VHF-bandet finns det 55 kanaler. Kanalerna vid kustradiostationen kallas för duplexkanaler och innebär att kustradiostationerna sänder och tar emot signaler på två olika frekvenser. Radioutbredningen hos antennen som är installerad på basstationen har riktverkan i vissa riktningar och dämpningar i andra. Detta kan ses i strålningsdiagrammet under kapitlet "Täckningsmodell" och avsnittet antennen. Andra faktorer som kan påverka radioutbredningen är förluster i basstationenssystemet, topologin hos området mellan sändare och mottagare samt väderberoende utbredningsegenskaper. Genom att hitta de tänkbara faktorer som påverkar signalutbredningen kan en täckningsmodell förutses. Det är förluster som finns i basstationen, radiolänken samt förluster vid mottagarantennen.

For the study of the EM (Electro Magnetic) wave propagation on the surface of the human body, the agar-gel phantom is used in the experiment. As the numerical analysis with the moment method which corresponding to the experiments, the relative permittivity of the homogeneous phantom plate becomes as the higher as the value of some thousands. The, numerical analysis shows that the other electrical properties can not contribute to the propagation characteristics in VHF resigon. These results assume that there is the unknown surface effect on the water in the region of VHF frequencies. Another experiment is conducted with varying the intervals of electrodes or forms and sizes, can give the optimal parameters. According to these experiments there is a frequency band which can be propagate on the human body in 40 MHz and near 100 MHz regions.

資料番号: AA0046920055

Electromagnetic (EM) waves associated with natural phenomena in VHF band have been observed by use of a novel dual frequency observation method. The observation method can observe not only natural EM waves but also reflected FM broadcasting waves. This paper shows some observation results of natural EM phenomena associated with galactic noise, solar flare, sporadic-E layer, the Leonid echo and the Geiyo earthquake., 資料番号: AA0045438069

The spectral analysis of data from three VHF radars (one high-Arctic and two mid-latitudes) show support for the universal spectrum theory for gravity waves in the lower atmosphere (altitudes of 2.0-11.0 km), provided that the impact of the off-vertical beam and noise are taken into consideration. This analysis also reveals that local gravity wave generation is of secondary importance, but still significant for determining the spectra. A total of eight spectral methods were considered and scrutinized for the purposes of determining gravity wave spectra from VHF radar data. A definition for the “best” method was given and examined. The method selected as the “best” for the analysis presented was a date-compensated discrete Fourier transform with a Hamming window.

Today’s and future communication systems in maritime rely on digital data communication between the ship and transceivers that are either on land, in air (satellite) or on sea. Analog voice communications is not an integrated part of future maritime communication system proposals. However, it is in general preserved in its functionality according to future maritime communication system proposals. In recent years parts of the dedicated voice spectrum was already reallocated for digital non-voice communication systems. Within this paper, we focus on the possible usage of digital voice communications in the maritime VHF frequency band regarding its technical feasibility, benefits, and challenges.

Die durchgeführten Simulationen und experimentellen Verifikationen zur Ermittlung der Antennenparameter bilden die Grundlagen zur Auslegung einer entfaltbaren Monopolantenne für den DLR-Satelliten BIROS (Bispectral InfrarRd Optical System) zur Feuerfernerkundung. Die auszulegende Antenne in Kombination mit einem Satellitenmodem soll als technisches Experiment auf BIROS eingesetzt werden, um die Erreichbarkeit von BIROS im Orbit zu erhöhen. Vom Satelliten BIROS aus sollen an Bord erkannte Feuerereignisse direkt via Satellitenmodem zum Nutzer übertragen werden und zwar unabhängig vom Standard-Datenkanal über S-Band.

The goal of this research is to perform a cost-effectiveness analysis of selected aerial platforms and suitable communication payloads for use as communication relays in support of distributed military operations. Aerial platforms, for the purpose of this study, include UAVs, towers and aerostats. A multi-objective analysis is utilized to compare dissimilar attributes together among the alternatives. Cost data for each system considered is presented. To analyze the cost-effectiveness of alternatives for different mission sets, three hypothetical scenarios are used including disaster relief, long-range relay, and the tactical user. This research identifies the most cost-effective aerial platforms and communication payloads for each scenario based on the authors' preferences. Future decision makers can utilize this study as a decision tool to match their own preferences. http://archive.org/details/costeffectivenes1094541375 Lieutenant Commander, United States Navy;Lieutenant, United States Navy Approved for public release; distribution is unlimited.

Text-dependent speaker verification over degraded radio channel is a challenging task. To better understand the research problem, the Institute for Infocomm Research (I2R) of Singa-pore has collected a corpus of voice recordings transmitted over marine VHF. Built as an extension of the RSR2015 database, the VHF-RSR2015 consists of recordings from 300 speakers of Part I of the RSR2015 database transmitted over VHF channel. Extending the RSR2015 database, we would like to facilitate the study of the VHF channel effect, therefore, keeping the acoustic environment the same as that of RSR2015. Performance benchmark of a text-dependent speaker verification engine is given as reference on the original RSR2015 database recorded at a sampling frequency of 16kHz, on a sub-sampled version of the same dataset at 8kHz and on the data after transmission through the VHF channel.

Le développement de l’électronique embarquée et miniaturisée est pleinement d’actualité de nos jours, dans les domaines tels que l’armement, la médecine, et les télécommunications. La miniaturisation des antennes large-bande, opérationnelles sur plus d’une décade, présentent un défi particulier. Ces travaux de thèse proposent de travailler sur la miniaturisation d’une antenne spirale, afin d’en réduire l’encombrement, à savoir son diamètre, tout en conservant au mieux ses caractéristiques de rayonnement et polarisation intrinsèques. Cette recherche sera appliquée à la bande des Très hautes Fréquence (Very High Frequencies – VHF), allant de 30MHz à 300MHz La géométrie inédite proposée consiste à associer à une antenne spirale un ensemble d’anneaux résonnants, dont le diamètre n’excède pas celui de la spirale, et permettant de diminuer la fréquence basse de fonctionnement. Pour un ensemble de cinq anneaux associé à la spirale, la réduction de la fréquence basse de fonctionnement est de plus de 30%. Pour deux antennes spirales de même fréquence basse de fonctionnement, l’antenne miniaturisée a donc un diamètre réduit de 30%, soit une surface réduite de 50%. Les performances de l’état de l’art d’après lesquelles les réductions sur le diamètre des antennes spirales n’excèdent pas 15% sont donc dépassées. De plus, d’après cet état de l’art, les méthodes de réduction appliquées aux antennes large bande dégradent en général le gain et l’axial ratio dans les bandes basses de fréquences de fonctionnement. La méthode proposée permet de conserver l’efficacité de l’antenne, voire de l’augmenter, dans les fréquences proches de la fréquence basse de fonctionnement. Le rayonnement de l’antenne spirale miniaturisée dans la bande passante de l’antenne sans anneaux n’est pour autant pas modifiée. Ces résultats très encourageant ont été confirmés par la mesure d’antennes spirales miniaturisées, réalisées pour un diamètre de 8cm et de 1m : une réduction de 30% du diamètre sans dégradation du rayonnement a été observée. Les mesures ont par ailleurs donné lieu à l’étude de la réalisation d’une antenne en bande VHF, avec pour implication les problématiques de réalisation (masse, encombrement, résistance mécanique) et de mesure (isolation, effets parasites en VHF avec une longueur d’onde de 4m).

Recent enhancements in military telecommunication systems for monitoring and tracking in low VHF range (30-80 MHz) implies the use of specific antenna measurement facilities to characterize either the antenna alone or the antenna mounted on a supporting structure which can be heavy and bulky. Conventional outdoor far-field antenna measurement ranges used at UHF frequency bands and above become poorly effective down in VHF frequency band due to ground effects and electromagnetic pollution. Other implementations such as indoor far-field or compact range are not suitable at these very large wavelengths.The multi-sensor near-field approach shows benefits in terms of compactness and measurement speed. However this approach involves considering and treating high levels of reflectivity of anechoic chambers, positioners and structures at these frequencies. The implementation of such an antenna measurement range thus requires identifying and characterizing the effects of each contributor on the measurement performance and accuracy.In a first step, the proposed paper focuses on the feasibility of an indoor measurement facility at VHF frequencies with reflectivity analyses of each constituting elements of the multi-sensor near-field range (anechoic chamber, mast, positioner and measurement probes). Performances of the ferrite tiles as a low frequency absorbing solution covering anechoic chamber walls are estimated through 3D EM simulation and analytical model. A global measurement error budget is established for different antenna directivity classes. In a second step, activities are dedicated to an outdoor near field range including analysis of reflectivity (floor, probes, arch, tent …) and estimation of system performance. Mechanical aspects to obtain a removable and transportable system are discussed and considered in the global budget error. Finally both indoor and outdoor multi-sensor solutions are compared in terms of performances to conclude on the feasibility of such facilities and to identify key points. Details on a new VHF probe currently under development will be given.

資料番号: AA0046920022

This paper examines the prospects for continuing market growth during the next 15 years by surveying both RF communications technology for systems which use or will use SAW devices. It is predicted that the SAW wireless label will be the largest SAW application. Also, it is predicted that the majority of SAW devices will operate at UHF in contrast to current SAWdevices which are primarily at VHF.

With the increasing demand for access to the crowded radio frequency spectrum, cognitive radios have been suggested as one solution. Cognitive radios would be frequency agile and able to sense their radio environment and opportunistically use empty spectrum. Spectrum sensing, monitoring a given band of spectrum to see if it is occupied, is an essential part of a cognitive radio. The preferred method of spectrum sensing is the energy detector, which does not require any a priori information about the signal to be detected and is computationally simple to implement. Man-made noise, impulsive in nature, has also become more prevalent with the widespread use of electronic devices. In this thesis, we took measurements of man-made impulsive noise in the broadcast digital television bands to measure its presence, power, and spatial correlation. The effects of impulsive noise on the detection performance of an energy detector were analyzed. Lastly, a wideband RF receiver was designed, built, and tested on the Virginia Tech campus, which would be well suited both to spectrum sensing and taking measurements of impulsive noise. Master of Science

Two large outbreaks of Ebola hemorrhagic fever occurred in Uganda in 2000 and 2007. In May 2011, we identified a single case of Sudan Ebola virus disease in Luwero District. The establishment of a permanent in-country laboratory and cooperation between international public health entities facilitated rapid outbreak response and control activities.

En aquest document es tracta el problema de la redundància del sistema de transmissió de senyals multiplexats de veu per fibra òptica i coure entre una instal·lació de control i el centre d'emissors associat a la mateixa. Per la seva naturalesa, es tracta d¿un servei crític, ja que de ell depèn la correcta comunicació entre les instal·lacions de terra i les aeronaus que són a dins del seu sector, tant en vol com a les diferents instal·lacions de l'aeròdrom. En este documento se trata el problema de la redundancia del sistema de transmisión de señales multiplexadas de voz por fibra óptica y cobre entre una instalación de control y el centro de emisores asociado a la misma. Por su naturaleza, se trata de un servicio crítico, ya que de él depende la correcta comunicación entre las instalaciones de tierra y las aeronaves que están dentro de su sector, tanto en vuelo como en las diferentes instalaciones del aeródromo.

The aims of the present study were to clarify the antenna function and radio frequency radiation (RFR) sensitivity of human subjects using theoretical calculations and field tests. The weak very high frequency (VHF) electromagnetic fields and spontaneous hand movements were recorded. Groups of university students, other volunteers and as a very interesting group, experienced well finders, were used as test subjects. The VHF field was studied using a spectrum analyser and tuneable narrow-band or broad-band meter with a dipole antenna. The hand movements were registered by potentiometric systems and electromyography (EMG). The test subjects (altogether n = 140) in different tests were walking, sitting in a cart being pulled slowly forward, or sitting in a moving car. The responses were observed and hand movements were recorded and analysed by personal computers. By visual inspection and using the Pearson’s correlation, the results of different individuals have been compared with the measured intensity of far fields of a radio mast. Reaction spots and graphs defined by different individuals in the same experiment areas have been compared to each other. Hand movement correlated with the reactions of the forearm and shoulder muscles, e.g., pronator teres and trapezius, by EMG measurements. The reactions of some persons correlated with each other. Experiments in a slow moving wagon and in a moving car showed a correlation between the test subjects’ hand movements and the intensity of below 1 mV/m radio and TV signals measured in the vicinity of the test subject. In open field tests different persons usually reacted in widely different ways. The most evident results were recorded near the buildings, where the radio waves reflected from the wall and patterns of standing waves were clear. Many VHF frequency modulated (FM) broadcasting signals were summed at these places at the same time. It is concluded that the spontaneous hand movement reactions occurred as a response of the human body to the gradients of the VHF field intensity. The reaction generally occurred in interference patterns of multipath propagation or standing waves originating from the radiation of FM radio and TV broadcasting transmitters and radiation reflected from the walls of buildings or from other objects. This non-thermal reaction was clearly observable as spontaneous arm movements by 39 percent of the 85 tested students. Tiivistelmä Tässä tutkimuksessa selvitettiin ihmisen herkkyyttä radiotaajuiselle säteilylle. Ihmisen toimimista radioaaltojen antennina tarkasteltiin teoreettisesti ja kenttäkokein. Heikkojen VHF-alueen radioaaltojen voimakkuutta ja tahattomia käsien liikkeitä rekisteröitiin valituilla koepoluilla. Koehenkilöinä on ollut yliopiston opiskelijoita ja muita vapaaehtoisten ryhmiä. Kiinnostavin ryhmä oli kokeneet kaivonkatsojat, joiden käsienliikereaktioihin radioaaltojen vaikutuksista löytyy viitteitä kirjallisuudesta. Radioaaltojen voimakkuuden vaihteluja mitattiin spektrianalysaattorilla ja laajakaistaisella VHF-alueen integroivalla mittarilla. Käsien liikkeitä rekisteröitiin potentiometriin perustuvilla liikeantureilla. Lihasten sähköimpulsseja rekisteröitiin elektromyografia- eli EMG-laitteella. Eri koesarjoissa koehenkilöt (yhteensä 140) kävelivät, istuivat hitaasti vedettävässä vaunussa tai istuivat liikkuvassa autossa. Reaktioita tarkkailtiin ja käsien liikkeet ja mitatut kentänvoimakkuudet rekisteröitiin ja analysoitiin tietokoneella. Eri koehenkilöiden tuloksia, reagointipaikkoja ja rekisteröityjä käyriä 5–35 km:n etäisyydellä mastoista tarkasteltiin silmämääräisesti. Pearsonin korrelaatiolaskentaa apuna käyttäen tuloksia verrattiin radiomastojen säteilyn voimakkuuteen. Eri ihmisten reagointikohtia ja käyriä samoilta koealueilta vertailtiin keskenään. Koeasetelmassa käsienliikkeiden todettiin korreloivan joidenkin kyynärvarren ja hartialihasten (mm. pronator teres ja trapezius) EMG-signaaleihin. Joidenkin koehenkilöiden tulokset korreloivat keskenään. Hitaasti vedettävässä vaunussa ja liikkuvassa autossa tehdyissä kokeissa tuli esille korrelaatio vartalon edessä olevien käsien loittonemis-lähestymis-liikkeiden ja koehenkilön välittömässä läheisyydessä mitattujen 1 mV/m -tasoisten radio- ja TV-signaalien voimakkuusvaihtelujen välillä. Avoimella kentällä henkilöt reagoivat hyvin eri tavoin. Parhaiten yhteys tuli esille rakennusten lähellä sijaitsevilla koealueilla, joissa radioaallot heijastuivat rakennuksen seinästä muodostaen selkeitä seisovan aallon kuvioita. Useat taajuusmoduloidut VHF-alueen radiosignaalit summautuivat näissä paikoissa samanaikaisesti. Johtopäätöksenä on, että tahattomat käsienliikkeet tapahtuvat kehon vasteena VHF-kentän voimakkuuden muutoksille. Reaktio tapahtui yleensä interferenssi-kuvioissa tai seisovissa aalloissa, jotka muodostuvat FM-radio- ja TV-lähetysten monitie-etenemisestä radioaaltojen heijastuessa rakennusten seinistä tai muista kohteista. Tämä ei-lämpövaikutustason reaktio oli selvästi havaittavissa olkapään tasalle koukistetun käden tahattomana ojennus-koukistus-liikkeenä 39 prosentilla testatuista 85 opiskelijasta.

U disertaciji je provedeno istraživanje tehničkih i tehnoloških aspekata digitalizacije sustava pomorskih VHF komunikacija. Predloženo rješenje uzima u obzir preporuke ITU-a za istraživanja problematike povećanja broja kanala u pomorskom YHF području, i to: za tehničke karakteristike uređaja, kodiranje govora, karakteristike prijenosnog medija, ocjenjivanje kvalitete signala, raspodjelu frekvencijskih pojaseva. Također su uvaženi i ostali parametri koji ograničavaju raspon mogućih rješenja. Predložak za analizu prednosti i slabosti digitalnih tehnologija prijenosa signala u disertaciji se izvodi iz iskustava kopnenih radiokomunikacijskih sustava budući da su se kopneni radiokomunikacijski sustavi razvijali iznimno brzo u proteklih dvadeset godina, uglavnom neopterećeni starijim tehnološkim rješenjima ograničenjima regulatornih agencija kao što je slučaj u pomorstvu. Istraživanje za potrebe disertacije provedeno je kroz nekoliko sustavno povezanih faza. Utvrđene su najprije karakteristike govornih signala radi odabira prikladnog načina kodiranja. Potom su ispitani i uspoređeni tehnički parametri šest kopnenih komunikacijskih sustava, te se na toj podlozi postavio idejni model digitalnog pomorskog YHF komunikacijskog sustava. Provedena je komparativna analiza kvalitete signala digitalnog sustava, postojećeg analognog sustava i alternativnog analognog sustava s udvostručenim brojem kanala. Izračunom kapaciteta pomoću Erlang C modela potvrđena je temeljna hipoteza da je digitalni sustav sposoban povećati broj raspoloživih komunikacijskih kanala, uz održavanje zadovoljavajuće razine kvalitete informacije. S obzirom na predvidive zahtjeve uspostave predloženog rješenja i probleme koji se mogu očekivati pri planiranju procesa prijelaza, disertacija završava sistematizacijom prednosti i problema implementacije predložene digitalne tehnologije., The dissertation explores the technical and technological aspects of digitalization of maritime VHF communications. The proposed solution takes into account the recommendations of the ITU defining research parameters for increasing the number of channels in the VHF maritime area. These include parameters such as: the technical characteristics of devices, speech coding, the characteristics of transmission media, signal quality assessment, distribution of frequency bands. Other parameters that limit the possibilities of increasing the number of channels in the VHF maritime area are also taken into consideration. Terrestrial radio communication systems have evolved extremely rapidly in the past twenty years, largely unencumbered by older technologic solutions and limitations of regulatory agencies and as such, they represent a valuable source of insight into possible solutions. Therefore, the framework for analyzing the strengths and weaknesses of digital signal transmission technology in the thesis is derived from the experiences of terrestrial wireless systems. The research was conducted through several systematically related phases. The first step was to establish the characteristics of the speech signal in order to select a suitable method of coding. The second part of the research examined and compared the technical parameters of six terrestrial communications systems. This comparison and evaluation later served for proposing a new conceptual model of a digital maritime VHF communications system. ln the third step, a comparative analysis was carried out in order to compare the voice signal quality for three alternative solutions: the proposed digital system, the existing analogue system and the alternative analog system based on a doubled number of channels. Channel capacity was calculated using the Erlang C model. Calculations confirmed the fundamental hypothesis that the proposed digital system is capable of increasing the number of available communication channels, while, at the same time, maintaining a satisfactory level of quality of the information carried. Given the expected hardships in adopting the proposed solution and problems that can be expected during the transition process, the dissertation ends with a systematization of the advantages and problems expected in the implementation of the proposed digital teclmology.

An algorithm of embedding the digital watermarks into speech signals transmitted through analog channels of VHF radio telephony of the maritime and aeronautical mobile services has been designed. For embedding DWM it was proposed to use the vector quantization of the complex envelope of narrow-band signal. DWM robustness to the intersymbol interference, multiplicative and additive interferences is provided, respectively, by the following means: 1) formation of narrow-band channels, 2) step-size adaptation in the transmitter and receiver, and 3) distribution of DWM energy over L samples. This algorithm makes it possible to implement the automatic identification of radiotelephone transmissions without the replacement of the standard radio communication equipment and variation of the operation procedures of radio telephony.

International audience; A novel VHF-CCP was developed for sterilization and decontamination of medical instruments. The sterilization process is a two-step process: at first, an evaporated liquid is set into the chamber, e.g. water. Afterwards, plasma is ignited either solely with the remaining water vapor or with hydrogen gas in addition. As a "proof-of-concept", microbiological investigations are presented. To mimic worst case conditions, microbiological investigations were carried out in a so called "process challenging device", a metal box with small slits (0.3 mm). Besides, the condensation process was investigated with a high-speed camera in combination with a distance microscope objective.

From radio beacons to EGNOS This article describes with images more than half a century of radio aids to air navigation. All the images, taken in the same location within Catania Fontanarossa airport, provides an historical perspective to the article about EGNOS and Civil Aviation published in the previous issue of GEOmedia.

Svrha studije je da se na jednom mjestu sakupe sva trenutna saznanja o učincima prijelaza na digitalno odašiljanje televizije kako na sam spektar frekvencija u VHF i UHF pojasu, tako i na mogućnosti razvoja novih radijskih tehnologija. U studiji se očekuju i predviđanja stanja u slijedećim razdobljima. Isto tako studija mora dati objašnjenja stanja u pojasevima frekvencija u kojima se ranije koristila analogna NMT mobilna tehnologija s prognozom primjene i razvoja radijskih tehnologija i u tom dijelu spektra.

Results from a WERA radar system in very high frequency (VHF) mode in a small coastal area (range of 7 km. resolution of 250 m) are compared with surface drifter data. The measurements are performed in the Gulf of La Spezia, a highly populated area characterized by a complex use of the territory, where monitoring of surface currents can play an important role in correct management. The drifters have been launched in clusters of 3-6 units, aimed at investigating the significant time and space variability of the flow. In particular, two clusters launched at the same location 2 days apart show strikingly different patterns of evolution. The first cluster is swiftly advected with little particle spreading, while the second cluster divides into two branches with significant drifter spreading. Radial velocities from radar and drifter data are compared. The difference is characterized by a RMS similar to 5 cm/s, on the lowest side of the RMS values reported in the literature. In-situ drifter trajectories are then compared with synthetic trajectories computed from VHF radar fields, and a separation rate of similar to 1 km/12 h between individual trajectories is found. Finally, the spreading patterns of the in-situ clusters are qualitatively compared with the synthetic clusters and in all cases the synthetic trajectories are found to correctly reproduce the patterns, including the drastic difference between the two launches from the same location. The in-situ trajectories appear to fall in the envelope of the synthetic ones. The positive results are likely to be due to a combination of factors and primarily to the high frequency and space resolution of the radar fields, as well as to the flow regime characteristic of protected areas. The results confirm that radar data are well suited for the study of coastal flows in limited areas with complex patterns of velocity and transport. (C) 2009 Elsevier B.V. All rights reserved.

L’objectiu principal del projecte és el disseny i la posterior implementació d’un sistema basat en la tecnologia RFID, que permeti integrar la cadena de comercialització entre botigues multimarca i fabricants. Es realitzarà una implantació pilot a 10 empreses repartides per tot el territori espanyol, per tal de convertir un dels seus corner (mobles expositors) en un corner RFID, el que anomenarem “Smart Corner”, on cada fabricant podrà obtenir informació directa i immediata de l’estoc, les vendes, i dels moviments dels productes exposats al seu Smart Corner, aquest coneixement ajuda a al fabricant a conèixer i gestionar de forma personalitzada les necessitats dels seus distribuïdors. La combinació entre tecnologia RFID i les comunicacions ajudarà a aconseguir els objectius.

Στόχος της παρούσας διπλωματικής εργασίας είναι η ηλεκτρομαγνητική μοντελοποίηση υπό βρoχόπτωση στις VHF και UHF περιοχές συχνοτήτων. Προκειμένου να εξαχθούν συμπεράσματα για την ποιότητα των παρεχόμενων υπηρεσιών (κυτταρική και δορυφορική τηλεφωνία, μετάδοση τηλεοπτικών σημάτων) προσδιορίζονται η ισχύς λήψης και μία σειρά από παραμέτρους. The aim of this master thesis is the RF modeling during rainfall for the VHF and UHF ranges. In order to infer conclusions for the quality of the supplied services (cellular and satellite telephony, transmission of television signals) the received power and a series of parameters are defined.

Kombinacijom kvalitetnog GPS senzora i minijaturnog VHF odašiljača na jednoj strani i ručnog GPS uređaja, »obogaćenog« VHF prijemnikom na drugoj strani, ostvaren je jednostavan, pouzdan i efikasan sustav koji omogućava praćenje kretanja potražnih, lovačkih, ali i »nestašnih« pasa ako odlutaju izvan vidokruga svojih vlasnika. Budući da efikasnost takvog sustava ponajprije ovisi o kvaliteti radiokomunikacije između (a) udaljenog senzora koji šalje podatke o svome položaju, i (b) uređaja koji ih prima, težište ispitivanja stavljeno je na utvrđivanje omjera količine emitiranih i primljenih podataka, na terenima različitih konfiguracija.