Pseudo-Random Number Generators for Vector Processors and Multicore Processors

Large scale Monte Carlo applications need a good pseudo-random number generator capable of utilizing both the vector processing capabilities and multiprocessing capabilities of modern computers in order to get the maximum performance. The requirements for such a generator are discussed. New ways of avoiding overlapping subsequences by combining two generators are proposed. Some fundamental philosophical problems in proving independence of random streams are discussed. Remedies for hitherto ignored quantization errors are offered. An open source C++ implementation is provided for a generator that meets these needs

On Hydraulic Constraints in Control of District Heating Systems

District heating systems make an important puzzle piece in the energy system of both today and tomorrow. When designing, simulating and controlling these systems, hydraulics play a vital role. The pressure generated by pumps has to drive sufficient flow throughout the system to satisfy the requirements of customers. Ensuring that the system is sufficiently pressurized is a challenging task already in current systems, and may become even more challenging in the transition to the 4th generation of district heating. In the first paper of this thesis, a demand response framework is suggested, which distributes the available flow to customers in a fair way. The framework aims to make it so that when the available pressure in the network is low, the buildings in the periphery should still be able to satisfy their heating needs. The second paper of this thesis extends previous methods for identifying greybox parameters for hydraulic district heating models. Previous methods of this type rely on more measurement points, and do not include the influence of the control valves situated in customer substations. These model parameters can then be used for simulation or control purposes. Together, the results presented in this thesis provide tools for better dealing with the hydraulic limitations in district heating systems. At the end, future work is outlined which may further pave the way for improved control that takes hydraulic limitations into account

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

Supersonic beams of hydrogen atoms, prepared selectively in Rydberg-Stark states of principal quantum number $n$ in the range between 25 and 35, have been deflected by 90$^\circ$, decelerated and loaded into off-axis electric traps at initial densities of $\approx 10^6$ atoms/cm$^{-3}$ and translational temperatures of 150 mK. The ability to confine the atoms spatially was exploited to study their decay by radiative and collisional processes. The evolution of the population of trapped atoms was measured for several milliseconds in dependence of the principal quantum number of the initially prepared states, the initial Rydberg-atom density in the trap, and the temperature of the environment of the trap, which could be varied between 7.5 K and 300 K using a cryorefrigerator. At room temperature, the population of trapped Rydberg atoms was found to decay faster than expected on the basis of their natural lifetimes, primarily because of absorption and emission stimulated by the thermal radiation field. At the lowest temperatures investigated experimentally, the decay was found to be multiexponential, with an initial rate scaling as $n^{-4}$ and corresponding closely to the natural lifetimes of the initially prepared Rydberg-Stark states. The decay rate was found to continually decrease over time and to reach an almost $n$-independent rate of more than (1 ms)$^{-1}$ after 3 ms. To analyze the experimentally observed decay of the populations of trapped atoms, numerical simulations were performed which included all radiative processes, i.e., spontaneous emission as well as absorption and emission stimulated by the thermal radiation. These simulations, however, systematically underestimated the population of trapped atoms observed after several milliseconds by almost two orders of magnitude, although they reliably predicted the decay rates of the remaining atoms in the trap. TheComment: 36 pages, 18 figure

Why are cultures warlike or peaceful? Test of regality theory on 186 non-industrial societies

Regality theory is a theory saying that people show a preference for strong leadership in times of war or collective danger, but a preference for an egalitarian political system in times of peace andRegality theory is a theory saying that people show a preference for strong leadership in times of war or collective danger, but a preference for an egalitarian political system in times of peace and safety. These psychological preferences in individuals are reflected in the political structure and culture of the society. A society in danger will develop strong nationalism, discipline, strict religiosity, strict sexual morals and perfectionist art. A society in peace will develop in the direction of egalitarianism and tolerance. The article is both theoretical and experimental. Regality theory is explained and the theoretical basis of the theory is extended with contributions from evolutionary game theory, biological life history theory and ecological theory. The predictions of social-level effects of collective danger are tested by various statistical methods exploring the relationship between intergroup conflict and a number of indicators of social structure and culture in 186 non-industrial societies of the past based on data from Murdock and White's standard cross-cultural sample as well as a subsample based on ethnographic records. It is confirmed that a high level of intergroup conflict is connected with a hierarchical political system, a strict and punitive justice system, a strict religiosity, a high feeling of group identity, strict sexual morals, a higher workload on children, and embellished and perfectionist artistic expressions. Four other predicted effects do not show statistical significance. Intragroup conflict influences sexual morals but not the other cultural variables. It is also found that the level of conflict can be predicted from environmental and technological factors. Regality theory is compared with authoritarianism theory and various cultural theories. While some of these theories appear to describe related or identical phenomena, it is found that regality theory is the theory that best predicts the statistical results. Regality theory has important applications in both the natural and the social sciences, including the study of many psychological, political and cultural phenomena

Signature Honors Thesis - Healthy Pals

In an initiative to improve the health of children in Pitt County, an 8-week nutritional curriculum was administered to elementary aged children at Grady White Boats Boys and Girls Club. With the first and last week being dedicated to the pre and post-test, the middle 6 weeks contained interactive learning activities meant to increase the participants’ knowledge of what constitutes healthy foods. An improvement in score on the post-test would indicate an increase in knowledge of nutrition. Out of six participants, four improved on their score, while one maintained their score, and one decreased in their score. It is determined that while there is an average increase in test scores, the sample of the study is too small to draw conclusions

On the Variation of Gravity Wave Activity through the Solar Cycle at the South Pole

Atmospheric dynamics comprise of a multitude of phenomena from various sources that affect the entire climate of the globe. Some of these phenomena include Atmospheric Gravity Waves which are ubiquitous features around the planet. They are important mechanisms for the transport of momentum and energy from the lower atmosphere to the upper atmosphere. The sun is the ultimate source of energy for the earth and the primary driver of atmospheric dynamics. The 11-year solar cycle of the sun has had a noticeable effect on the overall climate of the earth in the past. More recent work has seen the diurnal tides being directly influenced by the change in solar energy over the solar cycle at the South Pole. The different types of atmospheric waves interact with each other in complex manners that are still a subject of research today. Gravity waves are known to be modulated by solar tides and vice versa so a change in the tides will induce a change in gravity waves. The solar cycle influence on tides can then be seen overall in gravity wave wavelengths and speeds. A CCD Spectrometer is used to gather temperatures and brightness\u27s of two separate airglow layers in the upper atmosphere at 87km (OH) and 93km (O2). Two different years are chosen to be analyzed for solar cycle dependencies. One year is 2002, during the previous time of maximum solar activity and the other is 2010, just after the last minimum of solar activity. Time series of temperatures and brightness\u27s are analyzed for gravity waves activity though a lomb-scargle frequency analysis and a least-squares fit using a sinecosine wave model. Using gravity waves theory and four different detection methods, the vertical and horizontal wavelengths, phase speeds and group velocities are found for these waves during the 2002 data gathering season and the 2010 data gathering season. Most wave parameters are found to have an overall increase from 2002 to 2010 with the exception being the derived horizontal wavelengths. The calculated wave parameters are found to be in agreement with past gravity wave detections

Factors Affecting Utilization of Four New Child Welfare Programs in Hawai‘i.

M.A. Thesis. University of Hawaiʻi at Mānoa 2018

Rydberg states of helium in electric and magnetic fields of arbitrary relative orientation

A spectroscopic study of Rydberg states of helium ($n$ = 30 and 45) in magnetic, electric and combined magnetic and electric fields with arbitrary relative orientations of the field vectors is presented. The emphasis is on two special cases where (i) the diamagnetic term is negligible and both paramagnetic Zeeman and Stark effects are linear ($n$ = 30, $B \leq$ 120 mT and $F$ = 0 - 78 V/cm ), and (ii) the diamagnetic term is dominant and the Stark effect is linear ($n$ = 45, $B$ = 277 mT and $F$ = 0 - 8 V/cm). Both cases correspond to regimes where the interactions induced by the electric and magnetic fields are much weaker than the Coulomb interaction, but much stronger than the spin-orbit interaction. The experimental spectra are compared to spectra calculated by determining the eigenvalues of the Hamiltonian matrix describing helium Rydberg states in the external fields. The spectra and the calculated energy-level diagrams in external fields reveal avoided crossings between levels of different $m_l$ values and pronounced $m_l$-mixing effects at all angles between the electric and magnetic field vectors other than 0. These observations are discussed in the context of the development of a method to generate dense samples of cold atoms and molecules in a magnetic trap following Rydberg-Stark deceleration.Comment: 16 pages, 18 figure