955 resultados para radio transmitters


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Nowadays global business trends force the adoption of innovative ICTs into the supply chain management (SCM). Particularly, the RFID technology is on high demand among SCM professionals due to its business advantages such as improving of accuracy and veloc-ity of SCM processes which lead to decrease of operational costs. Nevertheless, a question of the RFID technology impact on the efficiency of warehouse processes in the SCM re-mains open. The goal of the present study is to experiment the possibility of improvement order picking velocity in a warehouse of a big logistics company with the use of the RFID technology. In order to achieve this goal the following objectives have been developed: 1) Defining the scope of the RFID technology applications in the SCM; 2) Justification of the RFID technology impact on the SCM processes; 3) Defining a place of the warehouse order picking process in the SCM; 4) Identification and systematization of existing meth-ods of order picking velocity improvement; 5) Choosing of the study object and gathering of the empirical data about number of orders, number of hours spent per each order line daily during 5 months; 6) Processing and analysis of the empirical data; 7) Conclusion about the impact of the RFID technology on the speed of order picking process. As a result of the research it has been found that the speed of the order picking processes has not been changed as time has gone after the RFID adoption. It has been concluded that in order to achieve a positive effect in the speed of order picking process with the use of the RFID technology it is necessary to simultaneously implement changes in logistics and organizational management in 3PL logistics companies. Practical recommendations have been forwarded to the management of the company for further investigation and procedure.

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The most common reason for a low-voltage induction motor breakdown is a bearing failure. Along with the increasing popularity of modern frequency converters, bearing failures have become the most important motor fault type. Conditions in which bearing currents are likely to occur are generated as a side effect of fast du/dt switching transients. Once present, different types of bearing currents can accelerate the mechanical wear of bearings by causing deformation of metal parts in the bearing and degradation of the lubricating oil properties.The bearing current phenomena are well known, and several bearing current measurement and mitigation methods have been proposed. Nevertheless, in order to develop more feasible methods to measure and mitigate bearing currents, better knowledge of the phenomena is required. When mechanical wear is caused by bearing currents, the resulting aging impact has to be monitored and dealt with. Moreover, because of the stepwise aging mechanism, periodically executed condition monitoring measurements have been found ineffective. Thus, there is a need for feasible bearing current measurement methods that can be applied in parallel with the normal operation of series production drive systems. In order to reach the objectives of feasibility and applicability, nonintrusive measurement methods are preferred. In this doctoral dissertation, the characteristics and conditions of bearings that are related to the occurrence of different kinds of bearing currents are studied. Further, the study introduces some nonintrusive radio-frequency-signal-based approaches to detect and measure parameters that are associated with the accelerated bearing wear caused by bearing currents.

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Kognitiiviteknologialla on ennustettu olevan disruptiivisia vaikutuksia sodankäyntiin. Kognitiiviteknologian avulla pyritään löytämään myös ratkaisu kasvavista datansiirtovaatimuksista aiheutuvaan radiotaajuisen spektrin ahtauteen. Tämän tutkimuksen keskiössä on kognitiivinen radio. Diplomityössä ennakoidaan niitä muutoksia, joita radion kognitiiviset ominaisuudet tuovat sotilaalliseen toimintaympäristöön. Tutkimuksessa etsitään kognitiivisen radion suorituskykyyn, suorituskyvyn rakentamiseen ja käyttöön liittyviä tekijöitä, jotka ovat merkityksellisiä sotilaallisesta näkökulmasta. Radion kognitiivisuutta käsitellään kongitiivisten ominaisuuksien, kuten adaptiivisuuden tai tilannetietoisuuden, kautta. Painopisteenä on kognitiivisten ominaisuuksien keskinäinen arvottaminen, mahdollisten vaikutusten tarkastelu operatiivisessa viitekehyksessä sekä tarvittavien toimenpiteiden kartoittaminen kognitiivisen tekniikan operatiivisen käytön mahdollistamiseksi. Tutkimuksen pohjalta esitetään kognitiivisten ominaisuuksien tärkeysjärjestys suorituskyvyn ja johtamisjärjestelmien kehittämisen näkökulmista ja alustavia operatiivisia vaatimuksia kognitiiviselle radiolle sekä kuvataan spektrin hallinnan kehittämismahdollisuuksia. Operatiivisia vaikutuksia tutkitaan myös uhkalähtöisesti eli arvioimalla, miten tietty kognitiivinen ominaisuus vaikuttaisi yleisimpiin tiedonsiirtoverkkoihin kohdistuviin uhkiin. Lisäksi työssä arvioidaan kognitiivisen radion käyttöönoton esteitä Puolustusvoimissa. Tutkimuksen päämenetelmä on delfoi, jota on täydennetty asiantuntijahaastatteluin sekä -arvioin. Kognitiiviselle radiolle on useita erilaisia määritelmiä. Kaikkia kriteerejä täyttävää kognitiivista radiota ei ole vielä olemassa, vaikka kognitiivisia ominaisuuksia radioissa on ollut pitkään. Kognitiivinen radio, tai jo pelkästään ohjelmistoradio kehittyneillä kognitiivisilla ominaisuuksilla, tuo huomattavia mahdollisuuksia parantaa langattoman tiedonsiirron toimintakykyä sotilaallisessa käyttöympäristössä. Merkittävin suorituskykylisä sotilaallisessa käyttöympäristössä saadaan seuraavista kognitiivisista ominaisuuksista: 1) dynaaminen spektrin hyväksikäyttö (DSA) 2) yhteyksien adaptiivisuus ja radioresurssien hallinta (SLA ja RRM) sekä 3) älykäs verkonmuodostus (SON ja RBR). Tiedonsiirtojärjestelmien ylläpito ja rakentaminen vaativat aiempaa enemmän suunnittelua ja ammattitaitoa, mutta toisaalta loppukäyttäjän osaamistasovaatimuksia voidaan laskea sitä mukaa, kun lähestytään 0-konfiguraatiojärjestelmiä. Radioiden kognitiivisuuden myötä voidaan myös passiivisiin uhkiin, esimerkiksi elektroniseen tiedusteluun, varautua aiempaa tehokkaammin. Aktiivisiin uhkiin, kuten häirintään, kognitiiviset ominaisuudet vaikuttavat jopa toiminnan fundamentteja muuttavasti. Tiedonsiirtojärjestelmien ohjelmistopohjaisuus nostaa kyberin merkitttävyyttä arvioitaessa eri uhkien kokonaismerkityksiä. Onnistunut kyberoperaatio voi tarkoittaa koko järjestelmän lamautumista tai vakavaa tietovuotoa. Kognitiivisten ominaisuuksien liittäminen osaksi sotilasradiojärjestelmiä on haasteellista. Käyttöönoton esteitä ovat osaamisen puute, lainsäädännön ja regulaation jäykkyys, tekniikan osittainen kypsymättömyys sekä tietoturvan hallinta. Spektri on muutoksessa, mikä tulee näkymään spektrin sirpaloitumisena vuoteen 2020 mennessä. Paine taajuushallinnan muuttamisesta kognitiivitekniikkaa sallivampaan suuntaan nousee erityisesti siviilipuolen kehittyvien mobiililaitteiden datansiirtomäärien kasvaessa. Lainsäädäntö antaa viranomai-sille suuret valtuudet säädellä spektrin käyttöä poikkeusoloissa. Tämä mahdollistaa sotilaallisten järjestelmien suunnittelun ja kehittämisen taajuusriippumattomasti jo normaalioloissa. Haasteena on spektrin hallinnoinnin kehittäminen esimerkiksi ennakoitua nopeammassa tilannekehityksessä. Spektriä tulisi hallita kokonaisturvallisuuden näkökulmasta joustavasti viranomaisten yhteisillä päätöksillä. Kognitiivisen radion tulisi tulevaisuudessa voida käyttää muille järjestelmille osoitettuja taajuusresursseja taajuuksien ollessa käyttämättömänä. Kognitiivista radiota kannattaisi kehittää taajuusvapaasti. Spektri tullee olemaan tulevaisuudessa yhä ahtaampi, ja tähän haasteeseen kognitiivinen radio tarjoaa osaltaan ratkaisun.

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One component of successful parenting is related to efficiency in foraging behaviour. The relationships among chick feeding, the size and type of food package, and length of parental foraging trips has not been well studied in seabirds. In addition, relatively few data have been collected on the activities of seabirds when foraging away from the nest site. The objectives of this study were: (1) to contrast productivity, feeding rate, and attendance patterns of individuals carrying a novel transmitter with a control group of birds; (2) to use radio-telemetry to assess the variability in foraging locations within and between individual male Common Terns; (3) to determine the seasonal variation in chick diet; (4) to determine for each transmittered bird, the relationships among the foraging patterns, parental behaviour, and seasonal reproductive success. The study took place over two years (1990-91) on a concrete breakwater 1 km offshore on Lake Erie near Port Colbome, Ontario. Ten pairs of terns in 1990 and 12 pairs in 1991 were radio-tracked by boat or car during the chick rearing stage. Concurrent behavioural observations documented the time each sex spent foraging or at the nest. The frequency and prey species composition of feeds to chicks were also recorded. The transmitters had negligible effects on the feeding frequency and brood attendance patterns of transmitter carrying birds. Peak nesting transmittered birds in 1990 and 1991 exhibited some inter-individual variability in foraging locations, however intraindividual variability was low. Birds foraged primarily to the west and northwest of the colony. Late nesters exhibited greater inter-individual variability, however intra-individual variability remained low for most birds. Neither group demonstrated sufficient variability to support the regular use of this colony as an "information centre". Individual transmittered birds had unique and predictable foraging patterns, and corresponding differences in feeding frequencies and brood attendance patterns, yet productivity was essentially equal between nests due to the impact and importance of stochastic events. Individuals that were recaptured in 1991 exhibited very similar foraging patterns to 1990, suggesting littie variability between years. Conservation of foraging patterns between years may have potential implications for mate choice decisions in future breeding seasons. Prey species delivered to chicks differed between morning and evening for peak and late nesters in 1990, but not 1991. Peak nesters in 1990 fed significantiy more Rainbow Smelt fOsmerus mordM) than Emerald Shiner (Notropis atherinoidesV this trend was reversed for late nesters who also fed large numbers of unidentified larval fish. No significant differences were found in 1991. Seasonal changes in prey species delivered to chicks is believed to be attributable to the temperature tolerances of the smelt and shiners, and the presence of large schools of larval fish during the late nesting season.

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The relationships among chick feeding, size and type of prey item, and foraging time away from the brood have not been well studied in seabirds. This study investigated spatial and temporal patterns of foraging and chick-provisioning among 23 radio-tagged male common terns nesting at Hamilton Harbour, Lake Ontario during 1991 and 1992. Telemetry data were collected concurrently with behavioural observations from an elevated blind. Terns fitted with transmitters did not differ from controls with respect to either brood attendance, patterns of chick mortality, species and size distributions of prey delivered to offspring, or chick-provisioning rates. There was a clear separation of parental roles: males were primarily responsible for feeding chicks while females allocated more time to brood attendance. The prey species most commonly delivered to chicks by adults were rainbow smelt (Osmerus mordax) and alewife (A/osa pseudoharengus), followed in importance by larval fish, emerald shiner (Notropis antherinoides), salmonids, and fathead minnows (Pimepha/es prome/as). The relative proportions of various fish speCies delivered to chicks by males differed over the course of each breeding season, and there was also much variability in species composition of prey between years. Sizes of prey delivered to chicks also differed between sampling periods. The modal size of fish brought to chicks during Peak 1991 was 1.5 bill lengths, while the majority of prey in Late 1991 were small larval fish. The reverse trend occurred in 1992 when small fish were delivered to chicks predominantly during the Peak nesting period. During periods when predominantly small fish were delivered to chicks, the foraging activity of radio-tagged males was concentrated within a two kilometer radius of the colony. The observed variation in prey composition and foraging locations during the study likely reflects temporal variation in the availability of prey in the vicinity of the colony. Males delivered fish to chicks at a constant rate, while females 4 increased their feeding frequency over the first six to ten brood days. The mean length of fish delivered to chicks by adults increased significantly with increasing chick age. As a group, within each nesting period, transmittered males either foraged predominantly in the same directional bearing (north during Peak 1991, south during Late 1992), or concentrated foraging activity in the immediate vicinity of the colony (Late 1991, Peak 1992). However, individual radio-tagged males exhibited unique and predictable foraging patterns, often favouring specific locations within these areas and differing in their secondary foraging patterns. Overall, the Lake Ontario shoreline between NCB Bay" (3.5 km south of colony) and the lift bridge canal (4 km north of colony) was the foraging area used most frequently by radiotagged males during the chick-rearing period. Foraging patterns of transmittered males at Windermere Basin are similar to patterns of peak-nesting common terns, but differ from those of late-nesters, at a nearby colony (Port Colborne, Lake Erie). Differences between the foraging patterns of late-nesting terns at these colonies likely reflect differences in annual patterns of fish availability between the two locations. No relationship was found between foraging proficiency of adults and survival of offspring. Stochastic factors, such as predation by black-crowned nightherons (Nycticorax nycticorax) and adverse weather conditions during the early stages of chick rearing, may be more important determinants of common tern breeding success than parental quality or fish availability.

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Letter (10 typed pages) addressed to Press and Radio Friends which is attached to an informal history of the Whirlpool Rapids Bridge. The letter was sent from A.E. Parsons, manager of the Whirlpool Rapids Bridge, n.d.

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A one minute radio advertising for the soft drink 7-Up featuring the voice of Eartha Kitt.

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Tesis (Maestro en Ciencias en Ingeniería Eléctrica) U.A.N.L.

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