Approximating multivariate distributions with vines

In a series of papers, Bedford and Cooke used vine (or pair-copulae) as a graphical tool for representing complex high dimensional distributions in terms of bivariate and conditional bivariate distributions or copulae. In this paper, we show that how vines can be used to approximate any given multivariate distribution to any required degree of approximation. This paper is more about the approximation rather than optimal estimation methods. To maintain uniform approximation in the class of copulae used to build the corresponding vine we use minimum information approaches. We generalised the results found by Bedford and Cooke that if a minimal information copula satis¯es each of the (local) constraints (on moments, rank correlation, etc.), then the resulting joint distribution will be also minimally informative given those constraints, to all regular vines. We then apply our results to modelling a dataset of Norwegian financial data that was previously analysed in Aas et al. (2009)

Distribution of periodic points of polynomial diffeomorphisms of C^2

This paper deals with the dynamics of a simple family of holomorphic diffeomorphisms of \C^2: the polynomial automorphisms. This family of maps has been studied by a number of authors. We refer to [BLS] for a general introduction to this class of dynamical systems. An interesting object from the point of view of potential theory is the equilibrium measure $\mu$ of the set $K$ of points with bounded orbits. In [BLS] $\mu$ is also characterized dynamically as the unique measure of maximal entropy. Thus $\mu$ is also an equilibrium measure from the point of view of the thermodynamical formalism. In the present paper we give another dynamical interpretation of $\mu$ as the limit distribution of the periodic points of $f$

Array E calibration curves

This ATM summarizes the scope and contents of the calibration curve data book and calibration magnetic tape which will be supplied to the MCC for ALSEP Array E downlink data conversion. Certain of the Array data channels require special conversions which are out of scope of the Apollo/Saturn Calibration Tape Format Mod 1; special reference to these channels is contained herein.prepared by A. Bedford

Single and dual queueing schemes with prioritised traffic scheduling and finite waiting room

Analysis of new schemes aimed at improving congestion in communications systems is vital for todays service providers. Many techniques are used to evaluate such schemes be it precisely via mathematics or approximately using simulation. This thesis introduces a new scheme, the multi priority dual queue (MPDQ). The MPDQ is the combination of two concepts, the dual queue introduced by [Hayes et. al., 1999] and prioritised traffic. The MPDQ is a system with finite waiting room with two queues where traffic upon arrival if finding the first queue full wait in the second queue if there is room. When a space becomes vacant in the first queue, a customer at the front of the second queue enters the back of the first, which is the queue that has the service centre at the front of it. The traffic can be of two or more classes. The analysis of such a system is complex, both analytically using queueing theory and approximately using simulation analysis. Both approaches are taken in this thesis. To begin, the new algorithmic approach used for the MPDQ is applied for the single buffer model. The steady state and waiting time distributions are obtained and later compared to the MPDQ. Next the performance characteristics are obtained by solving the steady state and waiting time distributions of a two class MPDQ. Preemptive and non-preemptive service disciplines are investigated. Maple is also used to solve the algorithm. To broaden the application of the MPDQ scheme, computer simulations using Arena are undertaken to extend the application of the scheme (and existing finite queueing models) to situations with more than two priorities, something that is extremely difficult to solve analytically. Using simulation, comparisons are undertaken for the single and dual queue schemes for more than two priorities with a variety of queueing disciplines used including First In First Out (FIFO), Last In First Out (LIFO), High Class First (HCF), and Low Class First (LCF). Network scenarios are also modelled to determine the performance of the MPDQ in this environment

Compositional End Members in Gale Crater, Mars

Geochemical data returned from the Mars Science Laboratory’s Curiosity rover over 1296 sols, has revealed a previously unforeseen martian geochemical complexity. Before Curiosity landed in Gale Crater, Martian SNC meteorite studies along with previous orbiter, rover and lander data showed Mars as being a predominantly basaltic planet with little magmatic differentiation. But through using ChemCam density contour plots to collate compositional data obtained by that instrument, we can identify 4 compositional end members in Gale sedimentary and igneous samples

Recreation and athletics at the University of Winnipeg, 1967-1983 : a brief history

iii, 28 p. : ill

A Survey of University Student Attitudes Toward the Language Lab

This article reports the results of a survey of student attitudes toward thelanguage lab at Southern Illinois University at Carbondale. The report notes that aninitial positive attitude toward the lab in the first semester becomes more negativeduring the second. The author suggests a need for new lab materials that maintain theinitial favorable attitude towards the lab

The relationship between schools, communities, and funding structures: A case study of Huron Valley Schools

Under Proposal A, all public schools in the state of Michigan receive a per-pupil foundation allowance. The context in which a school district exists is not a part of this centralized funding system. As a researcher and 30-year practitioner, I believe context matters and policy becomes relevant at the point of implementation. Equal funding does not automatically make it adequate. Therefore, I designed a case study of Huron Valley Schools to examine the causal relationship that exists between this centralized funding system, the school district, and the communities that exist in the district. To understand the current policies and practices of the district, I examined the history of school funding in Michigan, the development of Huron Valley Schools, and the historical development of each community within the school district were told. Secondary data and published books were used to complete the study. This case study highlights the value of context and the long-term implication of policy decisions. All policies have consequences, intended or unintended. Policymakers and school administrators, need to move beyond the immediate need and must consider not only the future need but how policies may play out in a particular context. State funding structures need to consider the context in which the district exists and adjust funding structures to adequately meet the unique context and need of each district

Comparative aspects of phytase and xylanase effects on performance, mineral digestibility, and ileal phytate degradation in broilers and turkeys

Two experiments were performed, using broilers or turkeys, each utilizing a 3 × 2 factorial arrangement, to compare their response to phytase and xylanase supplementation with growth performance, nutrient digestibility, and ileal phytate degradation as response criteria. For both experiments, 960 Ross 308 or 960 BUT 10 (0-day-old) birds were allocated to 6 treatments: (1) control diet, containing phytase at 500 FTU/kg; (2) the control diet with xylanase (16,000 BXU/kg); (3) the control diet supplemented on top with phytase (1,500 FTU/kg); (4) diet supplemented with 1,500 FTU/kg phytase and xylanase (16,000 BXU/kg); (5) the control diet supplemented with phytase (3,000 FTU/kg); and (6) diet supplemented with 3,000 FTU/kg phytase and xylanase (16,000 BXU/kg). Each treatment had 8 replicates of 20 birds each. Water and diets based on wheat, soybean meal, oilseed rape meal, and barley were available ad libitum. Body weight gain and feed intake were measured from 0 to 28 D, and feed conversion ratio (FCR) corrected for mortality was calculated. Ileal digestibility for dry matter and minerals on day 7 and 28 were analyzed in addition to levels of inositol phosphate esters (InsP6-3) and myo-inositol. Statistical comparisons were performed using ANOVA. Xylanase supplementation improved 28D FCR in broilers and turkeys. Increasing doses of phytase reduced FI and improved FCR only in broilers. In broilers, the age × phytase interaction for phosphorous digestibility showed that increasing phytase dose was more visible on day 7, than on day 28. Mineral digestibility was lower in 28-day-old turkey compared with 7-day-old turkey. InsP6 disappearance increased with increasing phytase levels in both species, with lower levels analyzed in turkeys. InsP6 disappearance was greater in younger turkeys (day 7 compared with day 28). In conclusion, although broilers and turkeys shared several similarities in their growth and nutrient utilization responses, the outcomes of the 2 trials also differed in many aspects. Whether this is because of difference in diets (InsP or Ca level) or differences between species needs further investigation

Modeling the emergence of universality in color naming patterns

The empirical evidence that human color categorization exhibits some universal patterns beyond superficial discrepancies across different cultures is a major breakthrough in cognitive science. As observed in the World Color Survey (WCS), indeed, any two groups of individuals develop quite different categorization patterns, but some universal properties can be identified by a statistical analysis over a large number of populations. Here, we reproduce the WCS in a numerical model in which different populations develop independently their own categorization systems by playing elementary language games. We find that a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference (JND), is sufficient to trigger the emergence of universal patterns that unconstrained cultural interaction fails to produce. We test the results of our experiment against real data by performing the same statistical analysis proposed to quantify the universal tendencies shown in the WCS [Kay P and Regier T. (2003) Proc. Natl. Acad. Sci. USA 100: 9085-9089], and obtain an excellent quantitative agreement. This work confirms that synthetic modeling has nowadays reached the maturity to contribute significantly to the ongoing debate in cognitive science.Comment: Supplementery Information available here http://www.pnas.org/content/107/6/2403/suppl/DCSupplementa