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The main purpose of this thesis is to combine modified GML algorithm with 2-D simulated annealing for estimation of signal arrival time in the UWB systems.In a dense multipath environment, the generalized maximum-likelihood (GML) algorithm can be used for the time-of-arrival (TOA) estimation. Nevertheless, the GML algorithm usually takes a long period of time, and sometimes fails to converge. Hence, a modified GML (MGML) algorithm is investigated. Two threshold parameters need to be determined in using the estimation algorithm. One threshold is to decide the arrival time range of estimated path, and the other, an amplitude threshold, is to judge whether the estimated path is true. Generally, the decision rule of thresholds may be based on the minimum error probability, which is defined as the sum of false alarm probability and miss probability. To mitigate the effects from noise and dense multipath interference, and to reduce the computational complexity of the algorithm, a method of threshold settings based on the minimum root mean square error (RMSE) criteria is discussed. In this scheme, the RMSE value for each candidate threshold pair in an appropriate region is computed. Constructing an accurate RMSE table and performing a full-scale grid search of adequate threshold settings can be very time-consuming. A 2-D simulated annealing process is adopted for finding the best pair of thresholds for use in the modified GML algorithm. The simulated annealing, different from the gradient descent, can avoid trapping into a local minimum in finding the best threshold pair. The resulting threshold pair makes the modified GML algorithm become more efficient in estimating the signal arrival time with an automatic search manner. Simulation results show that the proposed scheme can achieve better performance than the grid search approaches in UWB environments.

<p>Environmental enrichment (EE) is used to improve the wellbeing of animals in human care. One way of testing what resources an animal prefers to have access to, is to make it pay a price. The price is in the form of time or energy spent to get access to the resource. When measuring the motivation of animals it is useful to compare the resource which is to be evaluated to a resource with a known value. Food is often the comparator. The maximum price paid approach measures the highest price an animal is willing to pay for access to a</p><p>resource. In this study the motivation of a grey seal (Halichoerus grypus) for getting access to artificial kelp and live fish was measured. Food was used as the comparator. A large net cage with a weighted entrance and a nonweighted exit gate was used as the test arena. The seal had to enter it by opening the entrance gate which had increasing weights every day, in 10 steps up to 65 kg. The seal was not willing to pay any price for the live fish. The maximum price paid for the food was 60kg, and for the artificial kelp 10kg, i.e. 17% of the maximum price paid for food. The results suggest that neither</p><p>live fish nor artificial kelp was an attractive EE for this seal. However, the study also shows that spring (reproductive period) is not a good time to test motivation in grey seals.</p>

<p>Environmental enrichment (EE) is used to improve the life of captive animals by giving them more opportunities to express species-specific behaviours. Zoo elephants are one of the species that is in great need of EE because their environment is often barren. Before making EE permanent, however, it is wise to test first if it works as intended, to save time and money. Maximum price paid is one measure that can be used to assess if an animal has any interest in a resource at all. Food is often used as a comparator against EEs in these kinds of studies. The aim was to investigate if the maximum price paid concept could be used to measure the value of EEs for the two female Asian elephants at Kolmården and to find an operant test suitable for them for the experimental trials. Three series of food trials were done with each elephant, where they had to lift weights by pulling a rope with their mouth to get access to 5kg hay. The elephants paid a maximum price of 372 and 227kg, respectively. However, the maximum price the elephants paid for access to the hay was not stable across the three series of trials. Hence it is recommended that the comparator trials are repeated close in time to the EEs to be tested. The readiness by which these elephants performed the task makes it worthwhile to further pursue this approach as one of the means to improve the well-being of zoo elephants.</p>

Univ. der Bundeswehr, Diss.--München, 2003.

The reaction-diffusion master equation (RDME) is a stochastic model for spatially heterogeneous chemical systems. Stochastic models have proved to be useful for problems from molecular biology since copy numbers of participating chemical species often are small, which gives a stochastic behaviour. The RDME is a discrete space model, in contrast to spatially continuous models based on Brownian motion. In this thesis two accuracy issues of the RDME on unstructured meshes are studied. The first concerns the rates of diffusion events. Errors due to previously used rates are evaluated, and a second order accurate finite volume method, not previously used in this context, is implemented. The new discretisation improves the accuracy considerably, but unfortunately it puts constraints on the mesh, limiting its current usability. The second issue concerns the rates of bimolecular reactions. Using the macroscopic reaction coefficients these rates become too low when the spatial resolution is high. Recently, two methods to overcome this problem by calculating mesoscopic reaction rates for Cartesian meshes have been proposed. The methods are compared and evaluated, and are found to work remarkably well. Their possible extension to unstructured meshes is discussed.

A sign pattern matrix is a matrix whose entries are from the set {+,-,0}. The minimum rank of a sign pattern matrix A is the minimum of the rank of the real matrices whose entries have signs equal to the corresponding entries of A. It is conjectured that the minimum rank of every sign pattern matrix can be realized by a rational matrix. The equivalence of this conjecture to several seemingly unrelated statements are established. For some special cases, such as when A is entrywise nonzero, or the minimum rank of A is at most 2, or the minimum rank of A is at least n - 1,(where A is mxn), the conjecture is shown to hold.Connections between this conjecture and the existence of positive rational solutions of certain systems of homogeneous quadratic polynomial equations with each coefficient equal to either -1 or 1 are explored. Sign patterns that almost require unique rank are also investigated.

A gradual rise in Earth's surface temperature marks a transition from the late Paleocene to the early Eocene ca. 58-51 Ma. Paleocene/Eocene boundary (∼55.5 Ma) sediments deposited in the midst of this slow warming ubiquitously reveal evidence for a massive isotopically light carbon injection and an associated rapid but transient global warming event, or hyperthermal, that has been termed the Paleocene Eocene Thermal Maximum (PETM) and attributed to a carbon injection from multiple potential sources. The PETM has gained importance over the past two decades as a potential geologic analog to the modern anthropogenic carbon injection and climate change. However significant questions surrounding the nature of the carbon injection at the onset of the PETM remain. The Clarence River valley, located in the Marlborough region, South Island, New Zealand, contains a series of outcrops of lithified late Paleocene to early Eocene sediments originally deposited on a paleo-slope margin. Within these sections, the Lower Limestone Member of the Amuri Limestone Formation records the interval of interest. A Lower Limestone prominent recessed unit consisting of multiple marl-rich beds and recording a pronounced negative carbon isotopic excursion (CIE) marks the PETM at sections that have been bisected by tributaries to the Clarence River, including Mead Stream and Dee Stream. Here I detail and discuss Clarence valley Lower Limestone sections and relate these records to global trends with an emphasis on adding constraints to the PETM carbon injection. Specifically, I document the lithologic and carbon isotopic expression of the PETM and two younger paired sets of early Eocene events that, similar to the Mead Stream and Dee Stream PETM sections, reveal negative CIEs and expanded marl-rich units coincident to identical CIEs and condensed carbonate dissolution horizons in deep-sea sections. I further quantify the abundance of bioturbating macrofauna trace fossils through the PETM at both Mead Stream and Dee Stream and argue that New Zealand margin intermediate waters became hypoxic precisely coincident to the PETM carbon injection. In concert, these findings suggest a PETM carbon addition mechanism capable of both diminishing intermediate water dissolved oxygen and of repeated early Eocene injections. / U.S. National Science Foundation (NSF); Joint Oceanographic Institutions (JOI), Inc.

Many commercially grown apple cultivars have a biennial cropping habit, producing many small fruit in one year and few or none in the following year. The production of fruits is known to inhibit flower initiation for the following year. This undesirable trait is frequently managed by removing (thinning) some flowers or young fruit in years of heavy flowering which improves the size of remaining fruits, but does not reliably improve flowering in the following year. The effect of thinning on flower initiation is not well understood. Two mathematical models are developed describing the relationship between flowering in one year and the next. The first models the effects of thinning on return bloom and attempts to define maximum repeatable flower number. The second models how proximity of growing points may impact biennial bearing and maximum annual flower number. This second model may be useful to advance research into biennial bearing in apple.

Šis magistro darbas yra skirtas stochastinių ekstremumų stabilumo uždavinių sprendimui. Šiame darbe yra atlikta N stabilumo analizė, kai N yra pasiskirstęs pagal geometrinį, Sibuya ir Harris dėsnius. Taip pat yra paskaičiuotas konvergavimo greitis maksimumams ir atlikta konvergavimo greičio kompiuterinė analizė. Gautais rezultatais mes patvirtinome jau žinomą faktą, kad geometrinis N maks stabilumas ir N min stabilumas yra vienas kitą sąlygojantys. Taip pat gavome ir įrodėme naujus rezultatus, jog Sibuya ir Harris N maks ir N min stabilumai nėra vienas kitą sąlygojantys. / This master’s work is dedicated to solution of the stochastic extremums stability problems. In this work the analysis of N stability is done then N is distributed by geometrical, Sibuya and Harris laws. The convergence rate for maximums was constructed and also computerized analysis of results was done. In accordance with the main results, we confirmed the known fact that geometrical N max stability and N min stability are influencing each other. Also we obtained and proved new results, that Sibuya and Harris N max stability and N min stability are not influencing each other.