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2016 Uppsatser om Frequency altered feedback - Sida 61 av 135
Design of a Direct-conversion Radio Receiver Front-end in CMOS Technology
In this Master's thesis, a direct-conversion receiver front-end has been designed in a 0.18um CMOS technology. Direct-conversion receivers (DCR) have obvious advantages over the heterodyne counterpart. Since the intermediate frequency (IF) is zero, the problem of image is circumvented. As a result, no front-end image reject filter is required and the channel selection requires only a low-pass filter, which makes it easy to integrate directly on chip. However, the DCR also suffers from several drawbacks such as extreme sensitivity to DC offsets, 1/f noise, local oscillator (LO) leakage/radiation, front-end nonlinearity and I/Q mismatch.
En känsla av samhörighet : En utvärdering av Umeå universitetsbiblioteks övergång till RFID ur ett personalperspektiv
Denna utvärdering av Umeå universitetsbiblioteks (UB) övergång till RFID-teknik (radio frequency identification) tar upp hur personalen har upplevt konverteringstiden och övergången. Syftet var att undersöka den involverade personalens åsikter och attityder kring omställningen och de eventuella konsekvenser och effekter som RFID-övergången fört med sig.Undersökningen genomfördes med korta uppsökande intervjuer vars frågor utformats i samråd med Umeå universitetsbiblioteks projektledare för RFID-konvertering. Frågorna resulterade i kvantitativa svar men respondenterna gavs möjlighet att utveckla sina svar med egna reflektioner. Av de totalt 17 respondenterna var nio män och åtta kvinnor i åldrarna 32-64 år. Resultaten visar på en till stora delar nöjd respondentgrupp, majoriteten tycker att övergången till RFID har fungerat bra, de flesta känner sig opåverkade i sin yrkesroll efter införandet och endast ett fåtal har lämnat konverteringstiden med några bestående men som drabbat deras arbete eller de själva. Bland respondenterna finns det en generellt positiv inställning till RFID-teknikens framtid på arbetsplatsen och ett flertal hoppas på en vidareutveckling och utbyggnad av tekniken..
Design av mikrovågsövergångar
In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured.
Lärare och digitala verktyg i matematikundervisningen : En kvantitativ studie om lärares inställning och kompetens kring användningen av digitala verktyg i årskurserna F-3
The purpose of this study is to examine in what extent primary school teachers, teaching children in the age of 6 to 9, choose to use digital tools in their teaching of mathematics. I also want to examine what these teachers think, in terms of advantages and disadvantages, about using digital tools on their mathematics lessons. Finally I want to examine what skills they possess about digital tools.I am using a quantitative method to collect my data. The quantitative survey consisted of a questionnaire survey of ten questions that 38 primary school teachers have answered.The results of my study show that the teachers to some extent use digital tools when they teach mathematics and that the availability of various digital tools are generally good. But it turns out that the availability of tools is not a guarantee that they are used in teaching of mathematics.
Samforskning : en möjlighet i pågående terapi
Tom Andersen (1995) utvecklade samtal där terapeut och klient tillsammans utvärderar samarbetet i terapin, samtal med reflekterande förhållningssätt som senare kom att kallas för samforskningssamtal. Samtal med ombytta roller, där terapeuten får lära av klienten. Studier har visat att samforskningssamtalen ger terapeutiska effekter med ökad känslan av samhörighet, fördjupad samskapande process och hjälper terapin framåt samt ger terapeuterna ökade kunskaper om sig själva som terapeut. Syftet med denna studie är att belysa om samforskningssamtal kan ge möjligheter och betydelse i pågående terapi och i så fall vilka.-Hur upplevdes samforskningssamtalet?-Vad fick terapeut respektive patient syn på i samforskningssamtalet?-Vilken betydelse kan samforskningssamtalet ha framöver i terapin? Två samforskningssamtal har hållits och därefter har en intervju hållits med var och en av deltagarna.
Virtuella communityn: en fallstudie om independentskivbolags användning av virtuella communityn
The purpose of this thesis was to study the importance of virtual communities for independent record companies. It also aims to examine how these companies use virtual communities in their marketing activities and how to gain competitive advantages by working with virtual communities. A case study based on interviews was conducted with managers from two independent record companies, Music Is My Girlfriend Recordings and B&B Records. Our study has shown that virtual communities are important for independent record companies as tools for finding and addressing the right target market. Useful information about the members of these communities can easily be gathered with the use of the various search options that are available.
Debatten om bibliotekarieutbildningen ? inför förändringarna av utbildningen år 1972 respektive år 1993 ? sådan den återspeglas i bibliotekstidskrifter
The purpose of this thesis is to examine the debate in library journals and in official reports on the subject of library education in Sweden. We focus on two periods: the period just before the year 1972 ? when the library education was transformed into being occupationally-oriented and the period just before the year 1993, when the library education was transformed into being ?academised?. This Master?s thesis shows that the debate and the arguments among initiated people in the library world have had some impact on how the library education was transformed later on.
Vad styr förekomsten av sälg och asp? : en studie av olika beståndstyper inom Hamra kronopark, Dalarna
Aspen (Populus tremula L.) and goat willow (Salix caprea L.) are two important tree species in the aspect of nature conservation. Due to the elimination of forest fires, a former negative attitude towards deciduous trees in forestry and a strong herbivore pressure, these tree species have been negatively affected during the last fifty years. The aim of this study was to investigate whether the occurrence of aspen and goat willow could be related to either human impact or to site properties, such as ground moisture and vegetation type. A side study included an inventory of a number of cyanobacterial tree lichens on aspen and goat willow in order to try to relate the occurrence of these lichens species to stand history and stand properties.
The study was performed in Hamra State Forest in northern Dalarna. Nature reserves were compared with stands in managed areas.
Dolls 4R: Ett mått på kunskapsutveckling? : En studie om bedömning av studentens kunskapsutveckling
Aim: The aim of this study was to examine a way to measure students? knowledge development by using a self-made measure instrument based on William Doll?s postmodern curriculum.Question: Is it suitable to use an self-made measure instrument based on William Doll?s post-modern curriculum theory to measure development of knowledge?Methods: The study was based on process-hermeneutics and was focused on analysingcollege students? written and oral reflective thoughts. The data was collected over three lessons, where six students? written reflective thoughts were handed in. An observation was carried out each lesson for an extra control of validity.
Kärnkraft : Ett arbete för drifttekniker?
The gas turbines in the Swedish secondary reserve are reaching the end of their technical lifetime, hence alternative solutions need to be considered. One of the solutions thought to have the greatest potential is the use of so called consumptionreduction. By entering contracts with large consumers, agreements are made to reduce consumption in the event of major disturbances in the power system and thus being used as a secondary reserve. This thesis investigates the feasibility of consumption reduction as part of the secondary reserve. This has been achieved by developing a requirement specification for the disturbance reserve and by studying the technical and economic potential for consumption reduction among a range of consumers.The technical potential for consumption reduction that fulfils the requirements for participating in the secondary reserve are on average 750 MW in SE 3 and 98 MW in SE 4.
Adaptiv temperaturreglering av bostadshus
The control of indoor temperature must be able to handle large time constants and both measureable disturbances like outdoor temperature, and non-measurable disturbances, like waste heat from appliances. Due to cheaper microcontrollers (small computers with designated tasks) with better performance, more advanced and computation-demanding methods for control can be used.In this thesis, Generalized Predictive Control (GPC) has been implemented and tested on a theoretically derived model of a house. GPC states that a model of the system is estimated in every sample, and the control is carried out simultaneously, based on predictions of the model. Disturbances like solar radiation can be estimated and used in the control as well. The control signals are determined by quadratic programming, which makes it possible to consider conditions, for example limitations on the control signals.GPC requires a number of parameters to be defined, like model order and control signal penalty, but is relatively robust for variations in them.
Fördelning av frambensskador på ytliga böjsenan hos galopphästar :
Superficial digital flexor tendon injuries are common causes of premature retirement or pre-longed convalescence periods for race horses. The curve gradient at Täby Galopp race track is very small and most races as well as high speed training are done on the left rein.
It is believed that the horses left foreleg is under considerably more strain then the right foreleg when being ridden on the left rein during gallop at high speed. During gallop on the left rein the horse puts its entire weight on the left foreleg when regaining ground contact.
The purpose of this study has been to find out, through analyzing the statistics concerning the horses that visited the ATG clinic at Täby during a period between January 2003 and September 2006, whether there is a higher frequency of superficial digital flexor tendon injuries on the left leg rather than the right and if so, can this support the theory that the design of the race track in combination with continuous left rein races can be a contributing cause of these injuries.
The result of the study shows that 57% of the tendon injuries occurred on the left front leg and 38% on the right front leg. The difference is not large enough to support the above theory of the underlying cause of these injuries..
Energikartläggning och driftoptimering genom behovsstyrning i befintlig fastighet
Energy supply in Sweden year 2011 amounted to 577 TWh. The final energy consumption for industrial, residential and service was 379 TWh. Sweden has energy policy goals to reduce energy use in buildings. One of these goals is to reduce the energy use by 20 % in 2020 compared to the year 1995. An important step to achieve this goal is to target energy efficiency measures in existing buildings.
Arbetsklimatets betydelse för kriminalvårdares arbetsrelaterade attityder
För att bättre förstå vad som leder till frånvaro och frivilliga avgångar inom kriminalvården är det aktuellt att undersöka vilka faktorer som påverkar dessa beteenden. Syftet med denna studie var att undersöka vad ett antal faktorer i arbetsklimatet betydde för individers arbetsrelaterade attityder. Vidare undersöktes om effekterna av klimatvariablerna på attityden intention till uppsägning medierades av de arbetsrelaterade attityderna. Deltagare i undersökningen var kriminalvårdare (N = 90) på en anstalt i Norrtälje. Sammanfattningsvis tyder resultatet på att det varierade vilka klimatfaktorer som kunde predicera de olika attityderna.
Proprioceptionsträning inom fotboll : utveckling av den non-visuella sensomotoriken
Syfte och frågeställningar Syftet med arbetet var att undersöka om fotbollsspelare kan utveckla proprioception där visuell återkoppling systematiskt tas bort vid kontroll av bollen med fötterna.Frågeställningar:? Går det att utveckla förmågan att kontrollera bollen utan visuell återkoppling under en träningsperiod om fyra veckor och 12 träningspass? ? Hur förändras en fotbollsspelares prestation (kontroll av bollen) med avseende på en förbättrad proprioception med hänsyn tagen till: tid (sekunder), hastighet (varv/minut) samt antal tillfällen spelaren tittar respektive tappar boll?MetodTotalt 20 deltagare från ett pojkelitlag valdes ut och matchades inför träningsperioden in i en interventions- och en kontrollgrupp för att säkerhetsställa att båda grupperna var likvärdiga. Interventionsgruppen bestod av 12 deltagare, medelålder ± standardavvikelse (± SD) var 12,2 (± 0,2) år. Kontrollgruppen bestod av 8 deltagare, medelålder 12,0 (± 0,7) år. Interventionsgruppen har under fyra veckor genomfört fyra specifikt framtagna träningsövningar innehållandes uppvärmning inkluderat dribblingar och passningar, slalom, bollkontroll i lådram och smålagsspel.