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696 Uppsatser om Frequency-hopping - Sida 6 av 47

MPD-vågformer för helikopterradar

A helicopter based system equipped with a millimetre-wave fire control radar is studied for improvement of the detection probability for moving ground targets. The system is a pulse doppler radar that sends out the electromagnetic wave in repetitive pulses. The frequency in which radar sends this pulse is called Pulse Repetition Frequency (PRF). The velocity of the moving targets is measured by spectral analysis of the pulses received. With this sort of system some targets will not be possible to detect.

RCC-Jordfelsskydd, mätmodul för övertonsanalys

The majority of all power cuts that affects individuals and communities are caused by earth faults on the power transmission lines at 10kV and 20kV level [1]. If these power cuts could be eliminated, less disturbances and interrupts would lead to large amounts of money savings.Swedish Neutral has developed such a protection system. When an earth fault occurs power is injected into the neutral point of the transformer. The RCC (Residual Current Compensation) protection calculates a compensation current exactly 180 degrees out of phase to the fault current. Doing this, the voltage at the fault location becomes very close to zero, without affecting the power transmission.The protection system can only compensate automatically for the fundamental frequency (50Hz), and manually for the 3rd, 5th, 7th and 9th harmonics.

Konstruktionsforslag for kabelprovningsutrustning av serieresonanstyp

In order to decrease the disturbance from a cable testing equipment, the company Ericsson Network Technologies in Falun determined to design a new series resonant test system with a lower frequency. The new equipment is of series resonant type with a system frequency of 500 Hz. This equipment consists of an inductor, a capacitor and a voltage source. The voltage source is the same as the old one, the cable acts as the capacitor but the inductor has to be designed especially for the new equipment. In this thesis work several air coil inductor types were examined.

Att genom design effektivisera räddningsinsatsen för motorcyklister i trafikolycka

What if the emergency response directly knew exactly where to go and what to do if a road accident occured? During the last ten years the number of motorcyclists in Sweden has doubled. Every year, more than 300 riders are seriously injured and over 40 die in road accidents. Being found in time is critical to increase the chance of survival. The goal of this project is to use design methods to find a solution that enables a fast and adequate emergency response for motorcyclists and other unprotected road users..

Observatörer för skattning av verktygspositionen hos en industrirobot : Design, simulering och experimentell verifiering

This thesis approaches the problem of estimating the arm angles of an industrial robot with flexibilities in joints and links. Due to cost-cutting efforts in the industrial robots industry, weaker components and more cost-effective structures have been introduced which in turn has led to problems with flexibilities, nonlinearities and friction. In order to handle these challenging dynamic problems and achieve high accuracy this study introduces state observers to estimate the tool position.The observers use measurements of the motor angles and an accelerometer and the different evaluated observers are based on an Extended Kalman Filter and a deterministic variant. They have been evaluated in experiments on an industrial robot with two degrees of freedom. The experimental verification shows that the state estimates can be highly accurate for medium frequency motions, ranging from 3-30Hz.

Hållbar utveckling i Kungsängen : ett gestaltningsarbete med fokus på folkhälsa, biologisk mångfald och ekologisk dagvattenhantering

Tail-biting in pigs is an animal welfare issue and in Sweden during 2002 the producers lost tree million Swedish crowns because of tail biting. This economic loss depends on the pigs which are discarded at slaughter because of tail biting. Tail biting can be separated into two stages, "pre-injury" and "injury". The aim of this study is to investigate if tail biting depends on environment or genetic background.A lot of research on the environments effects on the behaviour of pigs but not so much on the genetic effects has been performed. The frequency of tail biting in pig farms influence among others of environment enrichment, ventilation, gender and breed of the pig.

Social Demokrati : Sociala medier, Politiker och Demokrati

The aim was to explore how the first page of a student newspaper has been changed over time since it was founded in the 1960´s.This thesis explores how the front page of the student newspaper Lösnummer has been changed since it was founded in 1966. It concerns the location and frequency of elements and it is based on theories of layout, the first page and visual communicationIn addition, the thesis develops a new kind of method for determining the location of elements on the type area. The method is based on the hexadecimal number system. It is formed as a grid which is placed on the first page to determine the location of the elements.It concludes that the frequency of elements had its peak during the 1970´s and has ever since decreased gradually. Image placement has gone from being scattered all over the front page to be centered and increase in size. .

A comparison of transporters? paddle use when unloading pigs at slaughter

Today, pigs are moved on farm, between farms, between countries and to abattoirs. This movement of live pigs requires handling practices that are designed for the purpose. The objective of this study was to research the use of paddle in moving pigs, to investigate if there were different methods of paddle practice, explore the time efficiency of different kinds of paddle use and if there were any time variations in methods that varied in intensity of touch. This study was done on two Swedish abattoirs for a total of five weeks. A total of 22 transporters working at two different abattoirs where studied during unloading of pigs at the abattoirs.

Relationen mellan cyklister och fotgängare vid Södra Älvstranden, Göteborg En utvärdering av trafiken på cykelstråket Älvsborgsbron - Centrum

This paper describes a method for wireless energy transfer via near-field electromagnetic inductionthat is inexpensive, simple and can be applied to almost any type of system, regardless of size andenergy demands.The method uses a primary unit consisting of an oscillator, amplifier and inductive coil thattransfers energy to a secondary unit consisting of a coil, rectifier and voltage regulator. Two typesof oscillators and several amplifier designs were realized and evaluated together with a multitudeof flat coils of both monofilar and bifilar type.The results show that it is important to use an oscillator whose frequency is dependent on theinductance of the connected transmission coil, such as the Colpitts oscillator. This is preferable toan oscillator with a preset frequency, such as a Schmitt-trigger oscillator..

Come on and let me know , Should I stay or should I go? : Job-hoppings effekter på individens kompetensutveckling

The aim with this essay is to investigate the attitude that employers have towards conflicts at the workplace and how this affects their way to prevent and deal with conflicts among employees. Another part of the essay is to discuss pedagogical issues related to learning through conflicts. With this aim and these questions of issues, we have found out which attitude employers have towards conflicts at the workplace as well as how they prevent and deal with them. We have also investigated which opportunities for further development employers sees in situations of conflict. This study is based on qualitative interviews with six women who are head of units within the communal area.

Optimering av informationsinsamlingvid prototyptillverkning

This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.

Blod, svett & tårar : En studie av vad som skapar varumärkestillknytning till träningscenter

We have examined how the dependence, identity and social bonds affect customer loyalty and attachment to a training centre. The method used is a survey on SATS Karlstad city where 128 respondents were asked, out of which 118 surveys were used in the final analysis. The data was analyzed using ANCOVA and multiple regressions.The result showed significant relationships on attachment between identity and dependence. Social bonds had no significant effect on the attachment a member have towards training centre. Customer loyalty was measured by how long the individual has been a member and his or her training frequency.

Passive acoustic diver detection

This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.

Den närståendes upplevelse av kommunikationen - förändring och strategianvändning vid Parkinsons sjukdom

The aim of the study was to investigate how a significant other of threepersons with Parkinson?s disease experienced the communication in conversation. Astructured interview and analysis of a video recorded conversation was performed.The questions in the interview were aimed at mapping the significant others?experience of communicative problems, their frequency, degree and conversationstrategies used by a significant other in conversation. The result showed that thesignificant others? experienced problems in communication related to the disease inseveral different areas for two of three participants with Parkinson?s disease.

Ordfrekvens och repetition i läromedlet Lieber Deutsch : En analys av den språkdidaktiska förankringen i ett svenskt läromedel i tyska

The aim of this study is to examine the word acquisition, focusing on the nouns and word exercises, in two Swedish textbooks for German in the upper secondary school. The chosen method for investigating the nouns was corpus analysis. The noun frequency and distribution in the textbooks were analysed and discussed in relation to research in second language acquisition. The Involvement Load Hypothesis by Batia Laufer and Jan Hulstijn was used to examine the exercises in the textbooks. The study showed that most nouns only occurred once in the textbooks, but the most frequent nouns were well spread in the textbooks.

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