Classifying Corruption

Time delays reduces the performance of any controlled system. If neglected in the design phase, the system may even become unstable when using the designed controller. Several power control strategies have been proposed in order to improve the capacity of cellular radio systems, but time delays are usually neglected. Here, it is shown that the problems can be handled by considering the time delays in the design phase in order to choose the appropriate parameter values. Most popular algorithms can be seen as special cases of an integrating controller. This structure is extended first to a proportional integrating (PI)-controller and then further on to a general linear controller of higher orders. Corresponding design procedures are outlined based on techniques, such as pole placement, from the field of automatic control. The PI-controller is a very appealing choice of structure, with better performance compared to an I-controller and less complex than a higher order controller. The benefits are further illuminated by network simulations

Markbaserade sensorer för insamling av skogliga data : en förstudie

En förutsättning för skoglig planering på alla nivåer är att man har en god uppfattning om tillståndet i den stående skogen. K valiten på de beslut som fattas kommer därför att vara direkt beroende av mängden och kvaliten på den information som samlats in. Sensorer som radar, lidar och olika typer av digitala kameror används idag med framgång för fjärranalys där skogen avbildas från ovan. Föreliggande arbete syftar till att belysa de tekniska förutsättningarna för att utnyttja modem sensorteknik även för markbaserade mätningar. Detta skulle i så fall öppna möjligheter att automatisera fångsten av skogliga data som därmed skulle bli kostnadseffektivare samtidigt som nya typer av data skulle bli tillgängliga. På ett tidigt stadium valdes följande tekniker ut för att närmare studeras med avseende på lämplighet att ingå i ett inventeringskoncept: • Lidar. Lidar är en laserbaserad teknik för att mäta avstånd och riktning till objekt. Laserns fördelar gentemot andra typer av sensorer är att mycket hög vinkelupplösning kan erhållas på signalen. Laser baserade sensorer framstår därför som mycket lämpliga för olika typer av scanning eller avståndsmätning. Nackdelen är att laserstrålen måste ha fri sikt för att kunna registrera ett objekt samt att det i dagsläget handlar om dyr och avancerad teknik. • Fotogrammetri i digitala bilder. Om avståndet till objektet i en bild och kamerans inre geometri är kända kan geometriska mätningar av exempelvis stamdiametrar göras i bilden. Genom att använda digitala bilder och bildanalys borde det vara möjligt att skapa program som mer eller mindre automatiskt detekterar och mäter diametrar på de stammar som är synliga i en bild. Objektavstånden tas lämpligen ut genom separat avståndsmätning med lidar eller genom stereomatchning av två eller flera bilder. • Radar. Radarsignalen använder betydligt lägre frekvenser än laser, vilket ger den intressanta egenskaper i skogsuppskatt ningssammanhang då man kan se igenom objekt mindre än halva våglängden. Nackdelen med lågfrekventa signaler är att man får en för dålig vinkelupplösning om man försöker att genom scanning ta ut vinkel och avstånd till de enskilda stammarna. Radar verkar däremot vara en mer framkomlig väg om man avser att hämta information ur den totala retursignalen. En viss uppfattning om diameter fördelningen skulle i så fall kunna fås genom att studera skillnaden i retursignalen från olika våglängder. • Ultraljud. Ultraljud kan användas enligt samma principer som radar. Fördelarna med ultraljudssensorer är att det finns enkla och billiga standardkomponenter. Nackdelen är att signalen dämpas under fården genom luften och måste därför kalibreras för förändringar i luftens temperatur och fuktighet. Inventeringens uppläggning har också betydelse för de olika teknikernas användbarhet. Om man inventerar enligt principen för tvåfassampling ställs olika krav på utrustningen beroende på om det är det stora primära samplet eller det mer noggranna sekundära samplet man samlar in. Vid insamlingen av det primära samplet försöker man samla in stora mängder data som är korrelerat med den variabel som man önskar mäta för att få ett så lågt representativt fel som möjligt. Generellt kan man därför säga att kvantiteten data är viktigare än kvaliteten på det samma vid insamling av det primära samplet. Detta gör att tekniker som samlar in data kostnadseffektivt men med låg precision blir intressanta, exempelvis radar och ultraljuds sensorer som registrerar ekon kontinuerligt medan utrustningen förs längs en linje. Om man däremot vill mäta in det sekundära samplet med sensorer krävs utrustning som mäter med hög precision på den enskilda provytan, vilket talar för tekniker som lidar och fotogrammetri i digitala bilder. Ett kanske mer realistiskt alternativ är annars att inventera det primära samplet med automatiska kostnadseffektiva metoder medan det sekundära samplet mäts in med traditionella manuella metoder.This MSc thesis was done at the Department of Forest Resources and Geomatics SLU, Umeå during the fall 1996 and spring 1997. A requirement for accurate forestry planning at all levels is knowledge about the condition of the forests today. The quality of the decisions made will therefore be proportional to the quality and amount of information collected. Sensors like radar, lidar and different types of digital cameras are today used quite successfully for remote sensing from aircraft or satellites. The purp ose of the thesis is to make a feasibility-study about ground-based use of these kinds of sensors in order to rationalise and improve forest inventory work. Following techniques where selected for a closer study oftheir qualities as ingredients in an inventory concept: • Lidar. Lidar is an abbreviation for light detection and ranging and is a laser­ hased technique to measure distance and reflection of an object. Compared to other kinds of sensors the lidar has a very high angular resolution. Therefor it is well suited for scanning and ranging where high accuracy is required. The disadvantage of the method isthat a clear sight to the object is needed and that the technique must still be considered advanced and expensive. • Photogrammetry in digital images. If the distance to the object and the intemal geometry of the camera is known for an image, measurements of for example tree diameters or the shape of the whole trunk can be made. By using digital pietmes and image processing it seerus possible to develop programs that more or less automatically detects and measure the desired variables. • Radar. The radar-based sensors are using much lower frequencies than the laser. This gives radar the characteristic of being able to see through objects half the size of the wavelength or less. This could be very valuable if radar are supposed to be used for forest inventory work since there will be a problem with undergrowth covering stems if methods that demands visual sight will be used. The disadvantage with using the appropriate wavelengths is that the angular resolution will be to low for scanning where the purpose is to measure each stem individually. If on the other hand the total sum of the signals in a seanned sector is analysed in order to extract information about the standing volume, radar seems like a very feasible technique for developing an effective forest inventory concept. • Ultras o nie. Ultrasonic can be used by the same theories as for radar. The advantage for ultrasonic compared to radar is that there is a supply of comparatively cheap and simple standard components. The disadvantage is that how much the signal will be reduced while transmitting through the air depends to a high grade of the atmospheric humidity and temperature, which means that calibration must be made. Another negative characteristic of ultrasonic is that the signal is sensitive for wind. The methods of in ventory used al so have an effect on the feasibility of the techniques. If double sampling is used there will be different requirements for the equipment depending on if it is data from the large primary sample or the more accurate secondary sample being collected. When collecting the primary sample i t' s necessary to collect a large amount of data to prevent errors that originates from the representation of the population. The quality of the collected data will therefore be less important. This means that techniques that collects large arnounts of data with high cost-efficiency but lacks in precision will be interesting, for example radar or ultra-sonie sensors that collects data continuously while moving. On the other hand if the purpose is to collect the secondary sample, equipment that measures with high accuracy, like lidar or photogrammetry in digital pictures will be required. Another, maybe more realistic alternative, is to use a cost-efficient sensor-hased technique to collect data from the primary sample and then use traditional manual circular plot sampling for the secondary sample

Evaluating parametric holonomic sequences using rectangular splitting

We adapt the rectangular splitting technique of Paterson and Stockmeyer to the problem of evaluating terms in holonomic sequences that depend on a parameter. This approach allows computing the $n$-th term in a recurrent sequence of suitable type using $O(n^{1/2})$ "expensive" operations at the cost of an increased number of "cheap" operations. Rectangular splitting has little overhead and can perform better than either naive evaluation or asymptotically faster algorithms for ranges of $n$ encountered in applications. As an example, fast numerical evaluation of the gamma function is investigated. Our work generalizes two previous algorithms of Smith.Comment: 8 pages, 2 figure

Satisfaction classes in nonstandard models of first-order arithmetic

A satisfaction class is a set of nonstandard sentences respecting Tarski's truth definition. We are mainly interested in full satisfaction classes, i.e., satisfaction classes which decides all nonstandard sentences. Kotlarski, Krajewski and Lachlan proved in 1981 that a countable model of PA admits a satisfaction class if and only if it is recursively saturated. A proof of this fact is presented in detail in such a way that it is adaptable to a language with function symbols. The idea that a satisfaction class can only see finitely deep in a formula is extended to terms. The definition gives rise to new notions of valuations of nonstandard terms; these are investigated. The notion of a free satisfaction class is introduced, it is a satisfaction class free of existential assumptions on nonstandard terms. It is well known that pathologies arise in some satisfaction classes. Ideas of how to remove those are presented in the last chapter. This is done mainly by adding inference rules to M-logic. The consistency of many of these extensions is left as an open question.Comment: Thesis for the degree of licentiate of philosophy, 74 pages, 4 figure

The Fourier dimension is not finitely stable

The Fourier dimension is not in general stable under finite unions of sets. Moreover, the stability of the Fourier dimension on particular pairs of sets is independent from the stability of the compact Fourier dimension.Comment: Improves one of the results of arXiv:1406.148

Vulnerability assessments of pesticide leaching to groundwater

Pesticides may have adverse environmental effects if they are transported to groundwater and surface waters. The vulnerability of water resources to contamination of pesticides must therefore be evaluated. Different stakeholders, with different objectives and requirements, are interested in such vulnerability assessments. Various assessment methods have been developed in the past. For example, the vulnerability of groundwater to pesticide leaching may be evaluated by indices and overlay-based methods, by statistical analyses of monitoring data, or by using process-based models of pesticide fate. No single tool or methodology is likely to be appropriate for all end-users and stakeholders, since their suitability depends on the available data and the specific goals of the assessment. The overall purpose of this thesis was to develop tools, based on different process-based models of pesticide leaching that may be used in groundwater vulnerability assessments. Four different tools have been developed for end-users with varying goals and interests: (i) a tool based on the attenuation factor implemented in a GIS, where vulnerability maps are generated for the islands of Hawaii (U.S.A.), (ii) a simulation tool based on the MACRO model developed to support decision-makers at local authorities to assess potential risks of leaching of pesticides to groundwater following normal usage in drinking water abstraction districts, (iii) linked models of the soil root zone and groundwater to investigate leaching of the pesticide mecoprop to shallow and deep groundwater in fractured till, and (iv) a meta-model of the pesticide fate model MACRO developed for 'worst-case' groundwater vulnerability assessments in southern Sweden. The strengths and weaknesses of the different approaches are discussed

Federal Arbitration Act and Application of the “Separability Doctrine” in Federal Courts

The classification of arbitration as substantive in Bernhardt v. Polygraphic Company jeopardized application of the federal Arbitration Act in diversity cases. However, in the recent case of Prima Paint Corporation v. Flood & Conklin Manufacturing Company, the Supreme Court found the Act to be a legitimate exercise of the federal commerce power and, hence, applicable in diversity cases involving arbitration agreements contained in interstate contracts. Furthermore, in interpreting the Act, the Court ruled that an arbitration provision is severable from other portions of an agreement for purposes of adjudicating contractual validity. However, by speaking only of federal court enforcement of the Act, the Court may have created severe forum-shopping problems. In order to avoid these problems, and vindicate the policy behind the Act, the coverage of the Act may subsequently be extended to the states

Nanophotonics with the scanning electron microscope

Physical size and power consumption are both increasingly important issues in increasing the data throughput of future optical interconnects, switches and ultimately even optical memory elements. In this respect, phase-change memories have proven to be strong candidates, with data recording done by switching the material between amorphous and crystalline phases, much in line with today's DVD/DVR technology. However, polymorphic systems exist in which crystalline-to-crystalline transitions can provide for higher-base logics as well. In particular, by coding each distinct optical characteristic by a unique label, the different optical cross-sections of absorption and scattering of the crystalline phases of a single nanoparticle can be used as a logical element

Fourier dimension of random images

Given a compact set of real numbers, a random $C^{m + \alpha}$-diffeomorphism is constructed such that the image of any measure concentrated on the set and satisfying a certain condition involving a real number $s$, almost surely has Fourier dimension greater than or equal to $s / (m + \alpha)$. This is used to show that every Borel subset of the real numbers of Hausdorff dimension $s$ is $C^{m + \alpha}$-equivalent to a set of Fourier dimension greater than or equal to $s / (m + \alpha)$. In particular every Borel set is diffeomorphic to a Salem set, and the Fourier dimension is not invariant under $C^m$-diffeomorphisms for any $m$.Comment: Minor improvements of expositio