10 research outputs found
Analysis of Coexistence of DRM Plus and FM Broadcasting Systems
This paper deals with DRM (Digital Radio Mondiale) Plus and FM (Frequency Modulation) radio broadcasting systems coexistence. It brings results based on measurement of mutual interferences of each to other. Minimal necessary value of the signal to interference power ratio is measured under the given reception criteria. Results are useful for broadcasting networks planning. Different DRM Plus modes (i.e. combinations of various protection levels and data carriers modulations) are assumed in the case of DRM Plus reception interfered with by FM broadcasting. The differences for various modes are crucial for coverage design of DRM Plus system, while protection ratios have been recommended for only two of eight modes until now. Corrections of protection ratios for other modes are proposed in this paper. Different waveforms types of modulating signal for interfering FM signal are tested. The both mono and stereo FM mode and various sound quality criteria are considered in the case of FM broadcasting reception interfered with by DRM Plus. The influence of peak to average power ratio reduction of interfering DRM Plus signal is observed
Powerline Kommunikation: Wesentliche Technologien um PLC in CE-GerÀte zu integrieren
In-house PLT (Powerline Telecommunication) enables new and highly convenient networking
functions without the need for additional cables on mains-powered devices. Since wireless
networks are not able to reach sufficient throughput between different rooms or even floors,
PLC is considered to be the ideal backbone home network medium, providing complementary
and seamless interaction with wireless networks.
The need to communicate information is not new. The historical overview of this thesis
compares the development of PLT to radio broadcast technologies. The consumer expects
technologies to operate without interferences. Today, there are coexistence problems between
these two technologies. Why does this happens, and how the problems can be resolved are the
main issues of this thesis.
Initial calculations of the channel capacity provide encouraging results for using the mains
cabling as a communication medium. Chapter 3 forecasts how PLT modems could develop in
the future. The usage of frequencies above 30 MHz will increase the throughput rate. Next, the
utilization of the 3rd wire (the protective earth) for communication enhances the coverage and
the reliability of powerline transmissions. The reception of common mode signals and the usage
of MIMO technologies enable 8 transmission paths between one pair of outlets, which
improves the performance of the bad, strongly attenuated channels.
Today, the main challenge for the mass deployment of PLT is the lack of harmonized international
standards on interoperability and electromagnetic interference. The absence of a standard
results in the undesirable situation of PLT modems interfering with technologies from
different vendors and also with radio applications. Solutions for solving these problems are
given in chapter 4 and chapter 5.
The approach of âSmart Notchingâ - monitoring the existence of receivable radio broadcast
stations at the time and location where a PLT modem is operating, received wide resonance in
the PLT and radio broadcast communities. âSmart Notchingâ, also called âDynamic Notchingâ
or âAdaptive Notchingâ is considered to be the key factor in solving the endless discussions
about the interferences to HF radio broadcast. Details on the creation of ETSI TS 102 578 and
the implementation of a demonstrator system is documented in chapter 5. Field tests conducted
together with the EBU verified the efficiency of the concept. The jointly executed tests by representatives
from the radio broadcast and the PLT communities became a historical event
which brought the two technologies, radio receivers and PLT modems, back into one house.
Finally, a vision of the future coordination of EMC and conclusions are presented.Heutige Modems zur Powerline Telekommunikation (PLT) können im Betrieb den Empfang
von Kurzwellen-Rundfunk beeintrÀchtigen, wenn Modem und Rundfunk-EmpfÀnger in
unmittelbarer Nachbarschaft betrieben werden. Eine neue Generation von PLT Modems, in
denen das Konzept von 'Smart Notching' - dem intelligenten EinfĂŒgen von LĂŒcken in das
Kommunikationsspektrum - implementiert ist, zeigt keine Interferenzen mit dem Empfang von
Rundfunkdiensten.
Das Rauschen auf der Niederspannungsinstallation enthÀlt neben sonstigen Signalen - durch
andere GerĂ€te hervorgerufen - aufgrund der Antennenwirkung Information ĂŒber Rundfunksender.
Beim âSmart Notchingâ erkennen PLT Modems am Betriebsort die Existenz von Rundfunksignalen,
indem sie das Signalspektrum auf der Netzleitung messen. Die Echtzeit-
Bewertung der aktuellen Situation am Betriebsort ermöglicht eine Adaption des PLT Systems.
Damit wird die Elektromagnetische VertrÀglichkeit nicht a priori (zum Herstellungs-Zeitpunkt)
durch Schirmung oder eine globale Reduktion des Sendepegels, sondern durch Design des
Verfahrens (welches wÀhrend des Betriebs angewendet wird) hergestellt.
Diese Doktorarbeit beschreibt nach einem kurzen Ăberblick zur Historie des Rundfunks
und der DatenĂŒbertragung ĂŒber das Energieverteilnetz Messungen zur Ermittlung der theoretischen
KanalkapazitĂ€t. AnschlieĂend wird ein Ausblick gegeben, wohin sich zukĂŒnftige PLT
Modems entwickeln werden. Dies sind vor allem der Frequenzbereich oberhalb von 30 MHz
sowie die Nutzung der dritten Kupferader in den Netzleitungen: der Schutzerde. Die Verwendung
von MIMO-Algorithmen (aus der kabellosen FunkĂŒbertragung (z.B. WiFi) bereits bekannt)
verbessert vor allem die Wahrscheinlichkeit, eine hohe Datenrate im GebÀude sicher zu
verteilen.
Sorge bereitet bei PLT ebenfalls die Koexistenz mit weiteren PLT-Systemen, sowie zu
xDSL. HierfĂŒr wird ein Vorschlag gemacht, um die Interferenzen zu nicht kompatiblen PLToder
DSL-Systemen zu vermeiden, ohne dass die Systeme sich gegenseitig gezielt Informationen
zusenden.
Das bereits oben erwĂ€hnte Konzept des âSmart Notchingâ wird detailliert erlĂ€utert und die
Implementierung eines Demonstrators auf FPGA-Basis dokumentiert. AbschlieĂend wird noch
beschrieben, wie âSmart Notchingâ gemeinsam mit der EBU getestet wurde und wie es seinen
Weg in die Welt der Standardisierung gefunden hat. Der Veröffentlichung des Standards ETSI
TS 102 578 wurde im Juli 2008 einstimmig von ETSI PLT zugestimmt
Advances in Sensors and Sensing for Technical Condition Assessment and NDT
The adequate assessment of key apparatus conditions is a hot topic in all branches of industry. Various online and offline diagnostic methods are widely applied to provide early detections of any abnormality in exploitation. Furthermore, different sensors may also be applied to capture selected physical quantities that may be used to indicate the type of potential fault. The essential steps of the signal analysis regarding the technical condition assessment process may be listed as: signal measurement (using relevant sensors), processing, modelling, and classification. In the Special Issue entitled âAdvances in Sensors and Sensing for Technical Condition Assessment and NDTâ, we present the latest research in various areas of technology
11th International Coral Reef Symposium Proceedings
A defining theme of the 11th International Coral Reef Symposium was that the news for coral reef ecosystems are far from encouraging. Climate change happens now much faster than in an ice-age transition, and coral reefs continue to suffer fever-high temperatures as well as sour ocean conditions. Corals may be falling behind, and there appears to be no special silver bullet remedy. Nevertheless, there are hopeful signs that we should not despair.
Reef ecosystems respond vigorously to protective measures and alleviation of stress. For concerned scientists, managers, conservationists, stakeholders, students, and citizens, there is a great role to play in continuing to report on the extreme threat that climate change represents to earthâs natural systems. Urgent action is needed to reduce CO2 emissions. In the interim, we can and must buy time for coral reefs through increased protection from sewage, sediment, pollutants, overfishing, development, and other stressors, all of which we know can damage coral health.
The time to act is now. The canary in the coral-coal mine is dead, but we still have time to save the miners. We need effective management rooted in solid interdisciplinary science and coupled with stakeholder buy in, working at local, regional, and international scales alongside global efforts to give reefs a chance.https://nsuworks.nova.edu/occ_icrs/1000/thumbnail.jp
Water productivity indices of the soybean grown on silty clay soil under sprinkler irrigation
The objective of this research was to compare the effects of different irrigation treatments on soybean [Glycine max (L.) Merr.] productivity and water use efficiency on experimental fields of the Maize Research Institute of Zemun Polje(Serbia), in 2007 and 2008. Four irrigation levels were investigated: full irrigation (I100), 65% and 40% of I100 (I65 and I40) and a rain-fed (I0) system. The crop water use efficiency (CWUE, also known as crop water productivity âCWP), irrigation water use efficiency (IWUE) and evapotranspiration water use efficiency (ETWUE) were used to assess the water productivity of each studied treatment. The efficiency of the same treatment differed between the years as it depended on seasonal water availability, weather conditions and their impact on seed yields. Maximum and minimum yields were obtained in the I65 and I0 treatments, averaging 3.41 t haâ1 and 2.26 t haâ1, respectively. Water use efficiency values were influenced by the irrigation levels. In general, CWUE values increased with the increased level of irrigation. In both growing seasons, IWUE and ETWUE decreased with increasing the seasonal water consumption and irrigation depth. On average, treatments I40 and I65 resulted in similar or higher CWUE and ETWUE than I100, in both growing seasons. I65 resulted in the highest IWUE, averaged over the two seasons, while I100 had the lowest IWUE. I65 could be proper for the soybean irrigated in Vojvodina when there is no water shortage and I45 could be used as a good basis for reduced sprinkler irrigation strategy development under water shortage
Street Furniture and the Nation State: A Global Process
In the popular imagination, street furniture has traditionally been understood as evoking a sense of national or local identity. From Parisâ metro entrances, DDR lampposts in Berlin, and Londonâs york stone pavements, the designed environment has been able to contribute to the unique qualities of a place. In some instances this was deliberate. In postwar Britain for instance, the Council of Industrial Design â a state-funded design organization - often appeared to measure the quality of street furniture on the basis of its national characteristics. On other occasions, the relationship between such objects and identity emerged accidentally. In Britain during the 1980s, for example, the replacement of Gilbert Scott's red telephone box with an alternative BT model provoked considerable debate. For many people, this act was not just a Conservative attack on nationalization and state-ownership, but also on the very fabric of British identity.
This understanding of street furniture has retained its currency for many years, and cities across the world have used street furniture to provide a sense of visual coherency for neighbourhoods in need of new identities, strengthening their character and improving the public's relationship to them. In this way, street furniture has been employed as a cipher for the narrative of regeneration, in which - as a means of altering the identity of a space - street furniture can project a new face upon the street.
Increasingly however, advertising companies are able to lever themselves into the street furniture market by offering to provide the service to the local authorities for free in return for advertising space. In offering this service, global companies like JC Decaux, Wall and Clear Channel command a huge amount of commercial power within the city. The excessive homogenization of street furniture coupled with the overwhelming presence of advertising which is increasingly sanctioned by local authorities keen to reduce costs, has resulted in the perception of poorer quality streets. Thus, the irony of regeneration is that by seeking to promote the unique identity of a city, many places often end up looking more and more alike.
This paper will examine recent developments in the process by which the street is furnished and the agents responsible. It will specifically look at how these changes have affected the relationship between street furniture and identity, and equally the effect this process has had on understandings of national design histories. Clearly, evaluating contemporary street furniture through the lens of the nation-state is of very little value, since the international differences between street furniture are considerably less marked than they used to be. This extraordinary aesthetic convergence is partly linked to economies of scale - after all, just how many different kinds of bus stop can Europe afford to have? Yet it also reflects some of the challenges posed by globalization and privatization of public space. This paper will reflect upon that process, and how these bigger narratives increasingly affect the landscape of the street