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1007 Uppsatser om Simple random sampling - Sida 1 av 68

En jämförelse av stickprovsmetoder vid mätning av radioaktivetet på en yta

This study compares the sample variance of the mean in a simple random sample (SRS) and a systematic sample from a surface. The study also compares the prediction error variance in a SRS and systematic sample from a random field. Recommendations are presented on which method to use in the clearance and exemption process in the nuclear industry. The results indicate that quadratic systematic sampling outperformed SRS in most instances and proved to be especially efficient in the presence of a long-ranged covariance function and high sampling intensity (i.e. short distances between observations).

Pseudoslumptalsgenerering : En studie av pseudoslumpsalgoritmer i allmänhet med fokus på C++11-biblioteketRandom samt implementation av en modifierad XORShift

Randomness is a complex area of computer science, where only pseudo random numbers are possible to generate algorithmically.This report presents established algorithms for random number generation by conducting a basic study of relevant literature, while testing distribution and speed of the algorithms contained within the C++11 Random library. The results are compared to the algorithm XORShift and a modified version of it. The study shows that the modified algorithm passes all tests in Small Crush, andthat the run time is shorter than for those in the Random library. The conclusion is that it is possible to, with simple means, modify an algorithm to outperform the algorithms of the C++11 Random library..

Lawsonia intracellularis : utvärdering av provtagning med tops : utvärdering av provtagningsteknik med tops vid diagnostik av Lawsonia intracellularis hos tillväxtgrisar

Lawsonia intracellularis is an important pathogen in the intestine, causing diarrhea and retarded (or poor) growth in pigs. Diagnostics is based on sampling of small amounts of faeces. Several publicated scientific papers mention the use of faecal swabs as sampling material for diagnosis in experiments and in prevalence studies. Therefore the need of an evaluation of this sampling technique is urgent since, to our knowledge, this has not previously been done. Here reported work compare the use of rectal swabs for feacal sampling, with sampling and analysis of 0.1-0.2 gram of faeces. The studie included twelve herds with a case history of earlier or ongoing problems with diarrhoea where Lawsonia intracellularis could be suspected as the causative agent. A total of 120 growing pigs where examined.

Riskbaserat provtagningsprogram för mikroorganismer i Gäddviks vattentäkt

Risk-based sampling program of microorganisms in the water source in northern SwedenAfter several disease outbreaks caused by parasites in the drinking water during the last years, it is more essential than ever to insure that the water supply companies have enough barriers to counteract the presence of microorganisms in the outgoing water. It is also discussed whether climate changes such as increased precipitation can have a connection to the increased cases of parasites in water sources. The water source at Gäddvik is Luleå municipality?s largest and provides drinking water to 64 500 of Luleå?s 74 000 inhabitants. The investigation of microorganisms in the water source, especially in the Lule River has not been as prioritized as the sampling of chemical parameters.

Advantages and disadvantages of different observation methods on a troop of wild olive baboons at a river in Southern Kenya

Every observation method has its advantages and disadvantages and a well-adopted method gives more reliable results. Factors affecting the choice of the most appropriate methods for recording foraging behaviours include species, group size, environment, seasons and age. The focus for this study was to determine which method is most appropriate for studying the foraging behaviour of a troop of 89 olive baboons (Papio anubis) living in a riverine forest by the Southern Ewaso Ng'iro River by Lale'enok Resource Centre in Kenya. To determine this, a literature study was carried out to compare methods from monkeys and apes. I found instantaneous sampling was the most common method with intervals of 5 minutes in most cited studies.

Utveckling och utförande av frekvensstudie vid Rapid Granulator AB

The object of this examination project is to produce a method of work sampling at Rapid Granulator AB. The aim is to perform the method at the company and evaluate if it is executable. The study is delimited to the basic construction of the 45-series in the assembly hall.Preparations to produce the method of the work sampling resulted in definitions of activities, a form and a product tree. Several days were spent studying the assembling to learn and understand the entirety.The work sampling result showed a large amount of no value adding time that was used in the assembling. Some of the activities could be reduced and we observed some problems during the assembly process.

Sedimentprovtagning av dagvattendammar som ett alternativ till flödesproportionell vattenprovtagning

Stormwater run-off from surfaces such as roads or rooftops is often polluted with heavy metals and nutrients. Many of these substances can cause great damage in biota if they end up in the recipient. In Sweden constructed wetlands and ponds for treatment of stormwater are frequently used, since research has shown that these treatment ponds are reducing stormwater pollution considerably to a low cost. The knowledge of these pollutant removal mechanisms and how follow-up and assessment of the ponds should be performed is still limited.To determine the pollutant removal efficiency of the stormwater ponds it is recommended that flow-weighted water samples are collected from both the inflow and the outflow of the pond. This method demands considerable resources of time and money for installations and analysis.

En slumpmässig vandring eller genomsnittlig återgång : Råder förutsägbarhet på Stockholmsbörsen?

This study has been conducted in order to determine the existence of predictability for the Stockholm stock exchange. With this purpose the random walk theory has been raised against the theory of mean reversion in order to determine which theory is the most substantial. Data has been collected from Nasdaq OMX Nordic and furtherly been processed using the statistical software EViews. Swedish listed companies? daily share values between 2000-2014 have been analyzed using two tests; an Augmented Dickey Fuller test and a Variance Ratio test.

Hybridmodeller för prediktiv modellering skapade med genetisk programmering.

Det finns idag ett stort behov av att kunna klassificera stora mängder data på ett effektivt sätt. Prediktiv modellering är ett område inom data mining där prediktioner kan utföras baserat på tidigare erfarenheter. Dessa prediktioner presenteras sedan i en modell. Avvägningen mellan tolkningsbarhet och träffsäkerhet är ett begrepp som beskriver hur träffsäkra modeller ofta är ogenomskinliga, medan genomskinliga modeller ofta har lägre träffsäkerhet. Detta är ett problem eftersom det finns ett behov av modeller som är både träffsäkra och tolkningsbara.I denna studie visas hur man kan gå till väga för att skapa en modell som har en träffsäkerhet i klass med en ogenomskinlig modell, men samtidigt har en högre tolkningsbarhet.

Effektivitet på den nordiska terminsmarknaden : bevis från OMX Derivatives Market

 I uppsatsen undersöks effektiviteten av de tre nordiska aktieindexterminerna OMXS30, OBX och OMXC20 vars underliggande index representerar den svenska, norska respektive den danska aktiemarknaden. Analysen baseras på den svaga formen av den effektiva marknadshypotesen och den närbesläktade random walk hypotesen. Aktieindexterminerna undersöks under perioden januari 1997 till december 2008 samt under perioder då den nordiska marknaden karaktäriseras av bull och bear perioder. Testresultaten av Augmented Dickey-Fuller (ADF) samt Kwiatkowski, Phillips, Schmidt och Shin (KPSS) testet tyder på att aktieindexterminerna följer en random walk och att nordiska aktieindexterminer är effektiva under den undersökta perioden. Då testen utförs för de kortare bull och bear perioderna erhålls motsägelsefulla resultat vilket medför att slutsatser om huruvida aktieindexterminerna är effektiva under dessa perioder ej kan dras. .

Test av svag marknadseffektivitet för OMX Stockholm 30

Studiens syfte är att se huruvida OMX Stockholm 30 är svagt effektiv. Studien bygger på de kurser Stockholmsbörsen publi-cerar för OMX Stockholm 30. Vi har valt en strikt de-duktiv ansats. Utgångspunkten är Famas teorier om den effektiva marknaden, där vi valt att inrikta oss på den svaga formen av effektivitet. Vi genomför ett antal tester för att se ifall vi kan urskilja ett mönster i index-kurserna eller om priserna följer en ?random walk?..

Monetära modellers prognosförmåga för den svenska kronans utveckling

Syftet med denna uppsats är att undersöka två monetära modellers prognosförmåga för den svenska kronan. Detta är den första studie som utvärderar prognoser på den svenska kronan under rörlig växelkurs. Modellerna som används är ?flexible price monetary model? samt ?sticky price monetary model?. Modellerna jämförs dels med en random walk-modell, men även mot varandra för att kunna påvisa eventuella skillnader modellerna emellan.

Ämnena Bild och Musik ur ett historiskt perspektiv

This research project is about how the subjects` art and music has been described under the 20th century in the Swedish school until today. The purpose with this research project is to do a text analysis that describes these subjects now and the last century, to illustrate the differences between today and the last century. Hence the size of this subject I have chosen some random samples out of the 20th century until today. I started to take these random samples from the first lyric I found about these subjects, and continued with these random samples in other lyrics from the middle of the 20th century until the year 2006. I just took these random samples from what I had found because I did not found some lyrics from earlier period of the 20th century.

Ants and termites in small-scale plantain farms in Uganda : a comparison between agroforestry and non-agroforestry farms

This study was conducted in Kkingo district, west of Masaka, Uganda. It compared soil macrofauna abundance in non-agroforestry farms with that of agroforestry farms. The agroforestry farms had participated in the Vi Agroforestry´s program between 1995 and 2006, and continued on their own after 2006, when Vi Agroforestry left the area. The soil macrofauna is important for soil structure and processes that are contributing to soil organ-ic matter decomposition and nutrient mineralization. They are also predators of potential pests.

Methods for Locating Distinct Features in Fingerprint Images

With the advance of the modern information society, the importance of reliable identity authentication has increased dramatically. Using biometrics as a means for verifying the identity of a person increases both the security and the convenience of the systems. By using yourself to verify your identity such risks as lost keys and misplaced passwords are removed and by virtue of this, convenience is also increased. The most mature and well-developed biometric technique is fingerprint recognition. Fingerprints are unique for each individual and they do not change over time, which is very desirable in this application.

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