Browsing by Subject "asymmetry"
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Item Essays on time series and causality analysis in financial markets(2009-05-15) Zohrabyan, TatevikFinancial market and its various components are currently in turmoil. Many large corporations are devising new ways to overcome the current market instability. Consequently, any study fostering the understanding of financial markets and the dependencies of various market components would greatly benefit both the practitioners and academicians. To understand different parts of the financial market, this dissertation employs time series methods to model causality and structure and degree of dependence. The relationship of housing market prices for nine U.S. census divisions is studied in the first essay. The results show that housing market is very interrelated. The New England and West North Central census divisions strongly lead house prices of the rest of the country. Further evidence suggests that house prices of most census divisions are mainly influenced by house price changes of other regions. The interdependence of oil prices and stock market indices across countries is examined in the second essay. The general dependence structure and degree is estimated using copula functions. The findings show weak dependence between stock market indices and oil prices for most countries except for the large oil producing nations which show high dependence. The dependence structure for most oil consuming (producing) countries is asymmetric implying that stock market index and oil price returns tend to move together more during the market downturn (upturn) than a market boom (downturn). In the third essay, the relationship among stock returns of ten U.S. sectors is studied. Copula models are used to explore the non-linear, general association among the series. The evidence shows that sectors are strongly related to each other. Energy sector is relatively weakly connected with the other sectors. The strongest dependence is between the Industrials and Consumer Discretionary sectors. The high dependence suggests small (if any) gains from industry diversification in U.S. In conclusion, the correct formulation of relationships among variables of interest is crucial. This is one of the fundamental issues in portfolio analysis. Hence, a thorough examination of time series models that are used to understand interactions of financial markets can be helpful for devising more accurate investment strategies.Item Forward Di-hadron Asymmetries from p + p at ?s = 200 GeV at STAR(2012-07-16) Drachenberg, James LucasOne unresolved question in hadronic physics is the origin of large transverse single-spin asymmetries, AN, observed in hadron production from high-energy polarized-proton collisions. Collinear perturbative Quantum Chromodynamics (pQCD) predicts that AN should scale with the quark mass, however, experiments have since reported large AN for inclusive hadron production. Recent measurements from RHIC experiments show examples of these asymmetries at forward angles in a kinematic region where pQCD cross-section calculations reasonably agree with measured cross-sections. Disentangling dynamical contributions to AN from hadro-production requires moving beyond inclusive measurements. One possibility is to investigate asymmetries in two-particle correlations due to Interference Fragmentation Functions (IFF) and the Sivers effect. In 2008, RHIC dedicated a portion of the run to transversely polarized proton collisions at sqrt(s) = 200 GeV. STAR was equipped with a Foward Meson Spectrometer (FMS) and a Forward Time Projection Chamber (FTPC), overlapping in the pseudorapidity range of 2.5 < eta < 4. By analyzing neutral pions with the FMS correlated with charged particles from the FTPC, correlation asymmetries can be measured at kinematics where large inclusive asymmetries have been measured. Correlations are measured for pi^0's with 2 < pT, pi^0 < 5 GeV/c and associated charged particles in two ranges of transverse momentum: 1 < pT, ch < 2 GeV/c and 0.5 < pT, ch < 1 GeV/c. IFF and Sivers asymmetries manifest themselves through the correlation of two particles from the same jet. These events are selected through a cut on the pair radius, delta R. Gain non-uniformities and electronics failures have resulted in large holes in trigger acceptance and associated particle acceptance, respectively. This non-uniform acceptance allows the Sivers and IFF effects to mix and distort the raw asymmetries. Techniques are developed to measure this leak-through by means of unpolarized yields and event weighting. They result in small corrections to the asymmetries. IFF and Sivers asymmetries both for xF > 0 and for xF < 0 are reported for forward-angle pi^0-charged particle correlations from polarized-proton collisions at sqrt(s) = 200 GeV. Asymmetries are shown corrected for full underlying-event and pileup backgrounds, as well as corrected only for pile-up contributions. It appears the asymmetries are less sensitive to delta R when corrected for the full underlying-event background. Unfortunately, statistics limitations preclude a firm conclusion.Item Kitcher's Problem with Asymmetry(2012-10-19) Shields, JannaiThe twentieth century was dominated by two rival views of scientific explanation. The first is the causal view in which causation is primitive. According to this view, the best explanations are the ones that tell us the cause of a phenomenon, organism, or state of affairs. The second is the unification view, which seeks to unify seemingly disparate bodies of knowledge. Philip Kitcher shook up the debate by synthesizing the two views. He developed a unification theory in which causation is derivative of explanation. The intuitive idea is that the best explanations are the ones that can draw the most conclusions from the fewest basic premises, and these premises just are the causal explanations. There is a problem though. Like any theory of scientific explanation, Kitcher must show that his respects explanatory asymmetry. For instance, we want our scientific theories to say that the height of a flagpole is explanatory of the length of the flagpole's shadow, and not vice versa. Kitcher's view has come under serious attack from Eric Barnes, who claims that Kitcher's theory cannot respect the problem of asymmetry. He gives three examples in which he thinks Kitcher's view fails. Todd Jones tried to defend Kitcher in a paper, but there is still much left to be said. One of his arguments, involving a Newtonian particle system, fails. The status of two of his other arguments is unclear. My goal is to step into the debate between Jones and Barnes and tip the scales in favor of the position that Jones defended. Additionally, I consider new potential cases of asymmetry and show how Kitcher's theory is equipped to accommodate these cases too.