Nominal Distribution Research Articles

Negative concord and nominal licensing in Xhosa and Zulu

Xhosa and Zulu nominals have restricted distributions when lacking an outer class prefix known as the augment. We argue that in negative contexts augmentless ([−A]) nominals bear negative concord features, uNeg, which must Agree with a negative licenser iNeg (Zeijlstra 2004). This accounts for the fact that some of them can be used as negative sentence fragment answers, and at the same time cannot appear in sentences without c-commanding negation. It also explains a clausemate requirement [S ...Neg...[−A]...] consistently reported by speakers of both languages in our study for all but subjunctive and (occasionally) neg-raising environments. We demonstrate that further distributional constraints attributed by Halpert (2012, 2015) to special Case-licensing needs of Zulu [−A] nominals are shared by [+A] DPs modified by kuphela–‘only’, and [+/−A] wh-phrases are subject to near-identical restrictions. This is a state of affairs that Halpert’s approach would not predict and cannot explain. We build on Sabel and Zeller (2006), and Zeller (2008) in attributing the pattern to incompatibility between [+focus] features characteristic of negative concord items, ‘only’-modified DPs, and wh-phrases, and [−focus] features of certain Zulu and Xhosa clausal positions. Thus all aspects of [−A] nominal distribution reduce to independently motivated features of the class of expressions to which they belong.

Load frequency control of a hydro‐thermal system under deregulated environment using biogeography‐based optimised three‐degree‐of‐freedom integral‐derivative controller

This study presents the load frequency control of an interconnected two-area power system under deregulated environment with area1 as a thermal system having two generating companies and area2 as hydro-thermal system. Appropriate generation rate constraint, and governor dead band are provided in the areas. Three-degree-of-freedom integral-derivative (3DOF-ID) controllers are used as secondary controllers in the areas whose performance is compared with that of two-degree-of-freedom integral-derivative (2DOF-ID) and single-degree-of-freedom controllers such as integral (I), integral-derivative (ID). Biogeography-based optimisation (BBO) technique is used for simultaneous optimisation of controller gains and electric governor parameters. Analysis of the dynamic responses reveal the superiority of 3DOF-ID controller over I, ID, and 2DOF-ID controllers, in terms of settling time, peak deviation and magnitude of oscillation. Sensitivity analysis proved that, BBO optimised parameters obtained at nominal conditions are robust. 3DOF-ID controller parameters obtained at nominal distribution companies participation matrix (DPM) are healthy enough and not necessary to optimise for change in DPMs. Variation in frequency bias coefficient (B) concludes that the best selection for B is equal to area frequency response characteristics. Similarly, selection of governor speed regulation parameter (R) infers higher value for thermal-system, while hydro-system should be kept comparatively low.

Robust Response-Guided Dosing

In response-guided dosing (RGD), doses are adapted to the uncertain progression of each patient's disease condition. A stochastic dynamic program was recently developed for RGD. We study its robust counterpart, where the dose-response distribution belongs to an uncertainty set. For interval uncertainty, we prove that it is optimal to administer higher doses in worsening disease. When a certain scaling of a nominal distribution describes the interval, optimal doses also increase in the scaling parameter. Theory is illustrated via numerical results.

Correcting Too Much or Too Little? The Performance of Three Chi-Square Corrections

This simulation study investigates the performance of three test statistics, T1, T2, and T3, used to evaluate structural equation model fit under non normal data conditions. T1 is the well-known mean-adjusted statistic of Satorra and Bentler. T2 is the mean-and-variance adjusted statistic of Sattertwaithe type where the degrees of freedom is manipulated. T3 is a recently proposed version of T2 that does not manipulate degrees of freedom. Discrepancies between these statistics and their nominal chi-square distribution in terms of errors of Type I and Type II are investigated. All statistics are shown to be sensitive to increasing kurtosis in the data, with Type I error rates often far off the nominal level. Under excess kurtosis true models are generally over-rejected by T1 and under-rejected by T2 and T3, which have similar performance in all conditions. Under misspecification there is a loss of power with increasing kurtosis, especially for T2 and T3. The coefficient of variation of the nonzero eigenvalues of a certain matrix is shown to be a reliable indicator for the adequacy of these statistics.

Hydrate Shell Growth Measured Using NMR.

Benchtop nuclear magnetic resonance (NMR) pulsed field gradient (PFG) and relaxation measurements were used to monitor the clathrate hydrate shell growth occurring in water droplets dispersed in a continuous cyclopentane phase. These techniques allowed the growth of hydrate inside the opaque exterior shell to be monitored and, hence, information about the evolution of the shell's morphology to be deduced. NMR relaxation measurements were primarily used to monitor the hydrate shell growth kinetics, while PFG NMR diffusion experiments were used to determine the nominal droplet size distribution (DSD) of the unconverted water inside the shell core. A comparison of mean droplet sizes obtained directly via PFG NMR and independently deduced from relaxation measurements showed that the assumption of the shell model-a perfect spherical core of unconverted water-for these hydrate droplet systems is correct, but only after approximately 24 h of shell growth. Initially, hydrate growth is faster and heat-transfer-limited, leading to porous shells with surface areas larger than that of spheres with equivalent volumes. Subsequently, the hydrate growth rate becomes mass-transfer-limited, and the shells become thicker, spherical, and less porous.

The difficulty of measuring the local dark matter density

The analysis of the vertical velocity dispersion of disc stars is the most direct astronomical means of estimating the local dark matter density, $\rho_{DM}$. Current estimates based on the mid-plane dynamic density use a local baryonic correction that ignores the non-local effects of spiral structure and significantly underestimates the amount of dynamically relevant gas; the additional gas plus the remaining uncertainties make it practically impossible to measure $\rho_{DM}$ from mid-plane kinematics alone. The sampling of inhomogeneous tracer populations with different scale-heights and scale-lengths results in a systematic increase in the observed dispersion gradients and changes in the nominal density distributions that, if not properly considered, can be misinterpreted as a sign of more dark matter. If the disc gravity is modelled using an infinite disc, the local variation in the vertical gravity due to the globally exponential disc components results in an underestimation of the baryonic contribution by as much as ~40% Given only the assumptions of stationarity, an axially and vertically symmetric disc, doubly exponential tracer and mass-component density profiles, a phenomenologically justified model for the cross-dispersion component $\sigma_{Rz}$, and a realistic model for $g_z$, it is possible to solve the full vertical Jeans equation analytically for the vertical dispersion $\sigma_{z}(z)$ and hence test the robustness of previous attempts at measuring $\rho_{DM}$. When the model parameters are estimated from SEGUE G dwarf star data, it is still not possible to explain the difference in behaviour seen in the simple thick- and thin-disc datasets reported by Buedenbender et al.. Rather than being a fundamental problem with the kinematical model, this effect appears to be a further sign of the difficulty of defining and handling kinematically homogeneous tracer populations.

SU‐E‐T‐642: PTV Is the Voxel‐Wise Worst‐Case of CTV in Prostate Photon Therapy

Purpose:To examine the adequacy of the planning target volume (PTV) dose distribution as the worst‐case representation of clinical target volume (CTV) dose distribution in prostate volumetric‐modulated arc therapy (VMAT) plans.Methods:Ten intact prostate cancer cases treated by VMAT at our institution were randomly selected. Isocenter was shifted in the three cardinal directions by a displacement equal to the PTV expansion on the CTV (±3 mm) for a total of six shifted plans per original plan. Rotationally‐perturbed plans were generated with a couch rotation of ±1° to simulate patient yaw. The eight perturbed dose distributions were recalculated in the treatment planning system using the same, fixed fluence map as the original plan. The voxel‐wise worst‐case CTV dose distribution was constructed from the minimum value per voxel from the eight perturbed doses. The resulting dose volume histograms (DVH) were evaluated for statistical correlation between the worst‐case CTV and nominal PTV dose distributions based on D95% by Wilcoxon signed‐rank test with significance level p ≤ 0.05.Results:Inspection demonstrates the PTV DVH in the nominal dose distribution is bounded by the CTV DVH in the worst‐case dose distribution. Comparison of D95% for the two dose distributions by Wilcoxon signed‐rank test gives p = 0.131. Therefore the null hypothesis cannot be rejected since the difference in median values is not statistically significant.Conclusion:The assumption that the nominal dose distribution for PTV represents the worst‐case dose distribution for CTV appears valid for the ten plans under examination. Although the worst‐case dose distribution is unphysical since the dose per voxel is chosen independently, it serves as a lower bound for the possible CTV coverage. Furthermore, this is consistent with the unphysical nature of the PTV. Minor discrepancies between the two dose distributions are expected since the dose cloud is not strictly static.Funding Support: NIH/NCI K25CA168984, Eagles Cancer Research Career Development, The Lawrence W. and Marilyn W. Matteson Fund for Cancer Research, Mayo ASU Seed Grant, and The Kemper Marley Foundation

Magnetic Determination of the Current Center Line for the Superconducting ITER TF Coils

The ITER tokamak includes 18 superconducting D-shaped toroidal field (TF) coils. Unavoidable shape deformations as well as assembly errors will lead to error fields in the final configuration, which can be modeled with the knowledge of the current center line (CCL). We are building a room temperature magnetic measurement system using low-frequency ac excitation current through the TF coil and arrays of pickup coils, fabricated with printed circuit board technology. Deviations from the expected shape of the CCL will be obtained by comparing the amplitude of magnetic flux measured at several locations around the perimeter of the TF coil, with values computed assuming the nominal current distribution. We present experimental results obtained with a cable placed in one-turn groove of a full scale radial plate.

Natural circulation characteristics analysis of a small modular natural circulation lead–bismuth eutectic cooled fast reactor

Small modular reactors (SMRs) have attracted particular attentions in recent years, and small modular natural circulation lead or lead–alloy cooled fast reactor (LFR) is one of the potential candidates for SMRs development. In the small modular natural circulation LFR, the natural circulation characteristics of primary cooling system is a coupled thermal-hydraulic problem of the core, hot and cold plenums, reactor internal parts and heat sink. Therefore, in order to study the thermal-hydraulic performance and safety features of the reactor, the understanding of natural circulation characteristics of primary cooling system is very important. In this work, a CFD simulation was conducted to analyze the natural circulation characteristics of LFR-10 primary cooling system during nominal condition, the velocity and temperature distribution of the reactor pool were illustrated and discussed, the core flow distribution behavior was evaluated. The simulation results show that, a stable natural circulation can be established in the primary cooling system, the current thermal-hydraulic design scheme is feasible, some design features of the cold pool are found that need some reconsideration. The coolant was distributed automatically at the core inlet region, the mass flow rate gradually decreased along the core radial direction, but the mass flow share of each core layer is inconsistent with its power share, the current core flow distribution design of LFR-10 need further analysis, Finally, a correlation was proposed to predict the relationship between the core mass flow rate and the core power under different conditions based on theoretical deduction and simulation results, which can be used to evaluate the heat remove capacity and the primary system natural circulation characteristics for LFR-10 under different operating conditions quickly.

The Problematic Forms of Nominalization in English: Gerund, Verbal Noun, and Deverbal Noun

This paper addresses a problematic issue concerning the three forms of nominalization: gerund, verbal noun, and deverbal noun. These nominals are problematic for two reasons. The first reason is that they mix different degrees of nominal and verbal properties, so the choice of these nominals for certain structure is not easily predictable. The second one is that there are many discrepancies concerning the terminology related to these forms used in linguistic references and studies. The confusing terminology is misleading for the researcher, teachers, and learners. The terms under investigation have different internal structures, but they share the same nominal functions and distribution within the sentence (subject, object, etc.). The study aims to point out the confusing discrepancies in terminology, the properties of these forms, the similarities and differences between these three forms, and accordingly their categories.

Robust, Non-Gaussian Wideband Spectrum Sensing in Cognitive Radios

In this paper, we propose detectors (both parametric and robust) for wideband spectrum sensing in cognitive radios (CR's). The proposed detectors are able to detect spectral activity over a wide frequency range, while assuming little knowledge about the signals of interest. The parametric detector is based on a locally optimal (LO) Neyman-Pearson (NP) test and assumes a known non-Gaussian noise distribution. The corresponding decision statistic of the LO NP detector is expressed in frequency domain, allowing to identify the active channels within the wide frequency band of interest. On the other hand, for situations in which the noise distribution is only approximately known, we propose a robust signal detector that is immune to deviations of the noise model from a certain nominal distribution. The proposed wideband robust detector is based on a robust spectral estimator and is formulated as a non-linear regression. This regression problem can be solved using a fixed-point iteration algorithm at a quadratic computational complexity, in contrast with the Newton's method which would have cubic complexity order. The simulation results show that the proposed detectors can achieve better detection performance in the presence of non-Gaussian noise, compared to existing detectors under the same conditions.

Assessing fit in Bayesian models for spatial processes

Gaussian random fields are frequently used to model spatial and spatial–temporal data, particularly in geostatistical settings. As much of the attention of the statistics community has been focused on defining and estimating the mean and covariance functions of these processes, little effort has been devoted to developing goodness‐of‐fit tests to allow users to assess the models' adequacy. We describe a general goodness‐of‐fit test and related graphical diagnostics for assessing the fit of Bayesian Gaussian process models using pivotal discrepancy measures. Our method is applicable for both regularly and irregularly spaced observation locations on planar and spherical domains. The essential idea behind our method is to evaluate pivotal quantities defined for a realization of a Gaussian random field at parameter values drawn from the posterior distribution. Because the nominal distribution of the resulting pivotal discrepancy measures is known, it is possible to quantitatively assess model fit directly from the output of Markov chain Monte Carlo algorithms used to sample from the posterior distribution on the parameter space. We illustrate our method in a simulation study and in two applications. Copyright © 2014 John Wiley & Sons, Ltd.

The robustness of coding and modulation for body-area networks

We consider transmission over body area networks. Due to the difficulty in assessing an accurate statistical model valid for multiple scenarios, we advocate a system design technique favoring robustness. Our approach, which is based on results in [12] and generalizes them, examines the variation of a performance metric when the nominal statistical distribution of fading is replaced by the worst distribution within a given Kullback-Leibler divergence from it. The sensitivity of the performance metric to the divergence from the nominal distribution can be used as an indication of the design robustness. This concept is applied by evaluating the error probability of binary uncoded modulation and the outage probability ? the first parameter is useful to assess system performance with no error-control coding, while the second reflects the performance when a near-optimal code is used. The usefulness of channel coding can be assessed by comparing its robustness with that of uncoded transmission.

SU-E-T-551: PTV Is the Worst-Case of CTV in Photon Therapy

Purpose: To examine the supposition of the static dose cloud and adequacy of the planning target volume (PTV) dose distribution as the worst-case representation of clinical target volume (CTV) dose distribution for photon therapy in head and neck (H&N) plans. Methods: Five diverse H&N plans clinically delivered at our institution were selected. Isocenter for each plan was shifted positively and negatively in the three cardinal directions by a displacement equal to the PTV expansion on the CTV (3 mm) for a total of six shifted plans per original plan. The perturbed plan dose was recalculated in Eclipse (AAA v11.0.30) using the same, fixed fluence map as the original plan. The dose distributions for all plans were exported from the treatment planning system to determine the worst-case CTV dose distributions for each nominal plan. Two worst-case distributions, cold and hot, were defined by selecting the minimum or maximum dose per voxel from all the perturbed plans. The resulting dose volume histograms (DVH) were examined to evaluate the worst-case CTV and nominal PTV dose distributions. Results: Inspection demonstrates that the CTV DVH in the nominal dose distribution is indeed bounded by the CTV DVHs in the worst-case dose distributions. Furthermore, comparison of the D95% for the worst-case (cold) CTV and nominal PTV distributions by Pearson's chi-square test shows excellent agreement for all plans. Conclusion: The assumption that the nominal dose distribution for PTV represents the worst-case dose distribution for CTV appears valid for the five plans under examination. Although the worst-case dose distributions are unphysical since the dose per voxel is chosen independently, the cold worst-case distribution serves as a lower bound for the worst-case possible CTV coverage. Minor discrepancies between the nominal PTV dose distribution and worst-case CTV dose distribution are expected since the dose cloud is not strictly static. This research was supported by the NCI through grant K25CA168984, by The Lawrence W. and Marilyn W. Matteson Fund for Cancer Research, and by the Fraternal Order of Eagles Cancer Research Fund, the Career Development Award Program at Mayo Clinic.

A direct approach for modeling ion-exchange residual stress distribution in glass

In this article, we propose a direct approach to model the residual stress in glass due to ion exchange. Rather than employing the traditional thermal strain analogy approach in literature, the nominal residual strain distribution due to ion exchange is addressed with direct analysis of ion-exchange volume change first. Then, based on the principle of superposition, the residual stress in ion-exchanged glass is then formulated with a direct approach in the framework of elasticity, and a complete solution for residual stress distribution is obtained with consideration of the asymmetric ion molar concentration distribution. Finally, a simple example is provided to demonstrate the validity of the fundamental formulations proposed in this article.

Multi-State Electric Field Analysis of 1-Tower-Double-Circuit HVDC Transmission Lines Based on Charge Simulation Method

Currently, there is little experience about design of the 1-tower-double-circuit DC transmission lines. But the electromagnetic field distribution under its lines is complicated. In order to study the nominal electric field distribution of 1-tower-double-circuit DC transmission lines under different situations and a variety of operating conditions, the currents with analytical solutions are used to simulate the discrete or uneven distributed continuous charge. In the works within an acceptable range, the linear equations are built to solve simulation charge according to the electromagnetic theory. And ground nominal electric field of 1-tower-double-circuit DC transmission lines is calculated. The nominal electric field distribution extreme value extreme under different arrangements and nominal electric field distribution under a variety of operating conditions are analyzed comparatively. In this paper, the results show that the arrangements of lines have effects on the distribution characteristics of nominal electric field in normal condition. When monopole or bipolar or the bipolar of one line doesnt work, the change of nominal electric field is pronounced, but their extremes reduce.

Resultant Electric Field Reduction With Shielding Wires Under Bipolar HVDC Transmission Lines

A time-domain method is presented to solve the dc ion flow field in bipolar transmission lines under which shielding wires are built to reduce the resultant electric field. In this method, the charge simulation method, the finite element method, and the finite volume method are used to solve the space-charge-free electric field, ion flow field, and current continuity equation, respectively. The method is validated by measurement results. Meanwhile, the shielding effect is explained theoretically from three aspects: the nominal electric field distribution, space charge injection, and space charge distribution. The ion filed formation can be illustrated clearly with this method. Relationships between configurations of transmission line and shielding wires are evaluated on the basis of calculation results.

몬테칼로 시뮬레이션을 이용한 ECV의 공차누적분석

Tolerance accumulation has serious effect on the performance of an assembled body. This paper proposes the method which analyzes tolerance accumulation using Monte Carlo Simulation. This method can predict tolerance distribution of fully assembled body using the dimensional tolerance distribution of each part to be assembled. In this analysis, it is assumed that the tolerance of each part has the nominal distribution or uniform distribution. This analysis method is applied to ECV(External Control Valve), and the accumulated tolerance of the fully assembled ECV is obtained from the analysis. The results show that initial tolerance given to each part do not meet the design requirement of ECV. Hence, the tolerances of each part are modified and the additional analysis with the modified tolerances yields the results which satisfy the design requirements of ECV.

Empirical Correction to the Likelihood Ratio Statistic for Structural Equation Modeling with Many Variables

Survey data typically contain many variables. Structural equation modeling (SEM) is commonly used in analyzing such data. The most widely used statistic for evaluating the adequacy of a SEM model is T ML, a slight modification to the likelihood ratio statistic. Under normality assumption, T ML approximately follows a chi-square distribution when the number of observations (N) is large and the number of items or variables (p) is small. However, in practice, p can be rather large while N is always limited due to not having enough participants. Even with a relatively large N, empirical results show that T ML rejects the correct model too often when p is not too small. Various corrections to T ML have been proposed, but they are mostly heuristic. Following the principle of the Bartlett correction, this paper proposes an empirical approach to correct T ML so that the mean of the resulting statistic approximately equals the degrees of freedom of the nominal chi-square distribution. Results show that empirically corrected statistics follow the nominal chi-square distribution much more closely than previously proposed corrections to T ML, and they control type I errors reasonably well whenever N ≥ max(50,2p). The formulations of the empirically corrected statistics are further used to predict type I errors of T ML as reported in the literature, and they perform well.

Early performance of Pinus radiata provenances in the earthquakeravaged dry river valley area of Sichuan, southwest China

A provenance experiment involving five native provenances and an Australian landrace of Pinus radiata (D. Don) was established over three sites in the dry river valley area of Sichuan, southwest China in 2004 in order to select the most suitable provenance for environmental planting on the dry, steep and degraded slopes to reduce soil erosion. Although with much lower soil moisture supply and mean minimum temperatures in winter compared to P. radiata provenance trials established elsewhere in the world, these sites are within the working limits of the species defined by previous climate modelling and matching. Because of the difficult site conditions and severe natural disturbances after the experiment was established, mortality was high across the three sites in comparison to provenance trials in other countries. The average mortality rate among the provenance by replicate planting units over the three sites varied from 16% to 76% four years after planting, and from 40% to 88% five years after planting. The repeated measurements of tree size over time were analysed using multilevel linear mixed models to derive growth curves for the mean, median, the 75th and the 90th percentiles of the size distribution of each provenance at each site. There were significant site effects on tree growth, but no significant interactions between site and provenance was detected. Among the six provenances, Cambria was the best performer in diameter, height and stem volume growth across all sites. The better than average and the best trees of this provenance, as represented by the 75th and 90th percentiles of the nominal stem volume distribution, were significantly larger than the Australian landrace, Ano Nuevo, and the two island provenances, Guadalupe and Cedros. Monterey was overall the second best performer behind Cambria. The Australian landrace, Guadalupe and Ano Nuevo had similar performances in general. Cedros was significantly and consistently inferior to all other native provenances and the Australian land race. Because the genetic base of the present Australian plantations was derived largely from Ano Nuevo and Monterey, the superior early growth performance of Cambria at such difficult sites brings a new promise to the search of P. radiata provenances for the vast dryland areas in New South Wales and other parts of Australia.