Wiener System identification using B-spline functions with De Boor recursion

A simple and effective algorithm is introduced for the system identification of Wiener system based on the observational input/output data. The B-spline neural network is used to approximate the nonlinear static function in the Wiener system. We incorporate the Gauss-Newton algorithm with De Boor algorithm (both curve and the first order derivatives) for the parameter estimation of the Wiener model, together with the use of a parameter initialization scheme. The efficacy of the proposed approach is demonstrated using an illustrative example.

Asymptotic expansions for Taylor coefficients of the composition of two functions

We give an asymptotic expansion for the Taylor coe±cients of L(P(z)) where L(z) is analytic in the open unit disc whose Taylor coe±cients vary `smoothly' and P(z) is a probability generating function. We show how this result applies to a variety of problems, amongst them obtaining the asymptotics of Bernoulli transforms and weighted renewal sequences.

Biomass functions and expansion factors in young Norway spruce (Picea abies [L.] Karst) trees

Roots, stems, branches and needles of 160 Norway spruce trees younger than 10 years were sampled in seven forest stands in central Slovakia in order to establish their biomassfunctions (BFs) and biomassexpansionfactors (BEFs). We tested three models for each biomass pool based on the stem base diameter, tree height and the two parameters combined. BEF values decreased for all spruce components with increasing height and diameter, which was most evident in very young trees under 1 m in height. In older trees, the values of BEFs did tend to stabilise at the height of 3–4 m. We subsequently used the BEFs to calculate dry biomass of the stands based on average stem base diameter and tree height. Total stand biomass grew with increasing age of the stands from about 1.0 Mg ha−1 at 1.5 years to 44.3 Mg ha−1 at 9.5 years. The proportion of stem and branch biomass was found to increase with age, while that of needles was fairly constant and the proportion of root biomass did decrease as the stands grew older.

Application of cylindrical distribution functions to wide-angle X-ray scattering from oriented polymers

A systematic approach is presented for obtaining cylindrical distribution functions (CDF's) of noncrystalline polymers which have been oriented by extension. The scattering patterns and CDF's are also sharpened by the method proposed by Deas and by Ruland. Data from atactic poly(methyl methacrylate) and polystyrene are analysed by these techniques. The methods could also be usefully applied to liquid crystals.

System identification of Wiener systems with B-spline functions using De Boor recursion

In this article a simple and effective algorithm is introduced for the system identification of the Wiener system using observational input/output data. The nonlinear static function in the Wiener system is modelled using a B-spline neural network. The Gauss–Newton algorithm is combined with De Boor algorithm (both curve and the first order derivatives) for the parameter estimation of the Wiener model, together with the use of a parameter initialisation scheme. Numerical examples are utilised to demonstrate the efficacy of the proposed approach.

Rhinocetin, a venom-derived integrin-specific antagonist inhibits collagen-induced platelet and endothelial cell functions

Snaclecs are small non-enzymatic proteins present in viper venoms reported to modulate haemostasis of victims through effects on platelets, vascular endothelial and smooth muscle cells. In this study, we have isolated and functionally characterised a snaclec which we named rhinocetin from the venom of West African gaboon viper, Bitis gabonica rhinoceros. Rhinocetin was shown to comprise α and β chains with the molecular masses of 13.5 and 13kDa respectively. Sequence and immunoblot analysis of rhinocetin confirmed this to be a novel snaclec. Rhinocetin inhibited collagen-stimulated activation of human platelets in dose dependent manner, but displayed no inhibitory effects on glycoprotein VI (collagen receptor) selective agonist, CRP-XL-, ADP- or thrombin-induced platelet activation. Rhinocetin antagonised the binding of monoclonal antibodies against the α2 subunit of integrin α2β1 to platelets and coimmunoprecipitation analysis confirmed integrin α2β1 as a target for this venom protein. Rhinocetin inhibited a range of collagen induced platelet functions such as fibrinogen binding, calcium mobilisation, granule secretion, aggregation and thrombus formation. It also inhibited integrin α2β1 dependent functions of human endothelial cells. Together, our data suggest rhinocetin to be a modulator of integrin α2β1 function and thus may provide valuable insights into the role of this integrin in physiological and pathophysiological scenarios including haemostasis, thrombosis and envenomation.

Smoothness of scale functions for spectrally negative Lévy processes

Scale functions play a central role in the fluctuation theory of spectrally negative Lévy processes and often appear in the context of martingale relations. These relations are often require excursion theory rather than Itô calculus. The reason for the latter is that standard Itô calculus is only applicable to functions with a sufficient degree of smoothness and knowledge of the precise degree of smoothness of scale functions is seemingly incomplete. The aim of this article is to offer new results concerning properties of scale functions in relation to the smoothness of the underlying Lévy measure. We place particular emphasis on spectrally negative Lévy processes with a Gaussian component and processes of bounded variation. An additional motivation is the very intimate relation of scale functions to renewal functions of subordinators. The results obtained for scale functions have direct implications offering new results concerning the smoothness of such renewal functions for which there seems to be very little existing literature on this topic.

Structural spoilers or structural supports? Unionism and the strategic integration of HR functions

The strategic integration of the human resource (HR) function is regarded as crucial in the literature on (strategic) human resource management ((S)HRM). Evidence on the contextual or structural influences on this integration is, however, limited. The structural implications of unionism are particularly intriguing given the evolution of study of the employment relationship. Pluralism is typically seen as antithetical to SHRM, and unions as an impediment to the strategic integration of HR functions, but there are also suggestions in the literature that unionism might facilitate the strategic integration of HR. This paper deploys large-scale international survey evidence to examine the organization-level influence of unionism on this strategic integration, allowing for other established and plausible influences. The analysis reveals that exceptionally, where the organization-level role of unions is particularly contested, unionism does impede the strategic integration of HR. However, it is the predominance of the facilitation of the strategic integration of HR by unionism which is most remarkable.

When do export subsidies have a redistributional role? Reply

Our differences are three. The first arises from the belief that "... a nonzero value for the optimally chosen policy instrument implies that the instrument is efficient for redistribution" (Alston, Smith, and Vercammen, p. 543, paragraph 3). Consider the two equations: (1) o* = f(P3) and (2) = -f(3) ++r h* (a, P3) representing the solution to the problem of maximizing weighted, Marshallian surplus using, simultaneously, a per-unit border intervention, 9, and a per-unit domestic intervention, wr. In the solution, parameter ot denotes the weight applied to producer surplus; parameter p denotes the weight applied to government revenues; consumer surplus is implicitly weighted one; and the country in question is small in the sense that it is unable to affect world price by any of its domestic adjustments (see the Appendix). Details of the forms of the functions f((P) and h(ot, p) are easily derived, but what matters in the context of Alston, Smith, and Vercammen's Comment is: Redistributivep referencest hatf avorp roducers are consistent with higher values "alpha," and whereas the optimal domestic intervention, 7r*, has both "alpha and beta effects," the optimal border intervention, r*, has only a "beta effect,"-it does not have a redistributional role. Garth Holloway is reader in agricultural economics and statistics, Department of Agricultural and Food Economics, School of Agriculture, Policy, and Development, University of Reading. The author is very grateful to Xavier Irz, Bhavani Shankar, Chittur Srinivasan, Colin Thirtle, and Richard Tiffin for their comments and their wisdom; and to Mario Mazzochi, Marinos Tsigas, and Cal Turvey for their scholarship, including help in tracking down a fairly complete collection of the papers that cite Alston and Hurd. They are not responsible for any errors or omissions. Note, in equation (1), that the border intervention is positive whenever a distortion exists because 8 > 0 implies 3 - 1 + 8 > 1 and, thus, f((P) > 0 (see Appendix). Using Alston, Smith, and Vercammen's definition, the instrument is now "efficient," and therefore has a redistributive role. But now, suppose that the distortion is removed so that 3 - 1 + 8 = 1, 8 = 0, and consequently the border intervention is zero. According to Alston, Smith, and Vercammen, the instrument is now "inefficient" and has no redistributive role. The reader will note that this thought experiment has said nothing about supporting farm incomes, and so has nothing whatsoever to do with efficient redistribution. Of course, the definition is false. It follows that a domestic distortion arising from the "excess-burden argument" 3 = 1 + 8, 8 > 0 does not make an export subsidy "efficient." The export subsidy, having only a "beta effect," does not have a redistributional role. The second disagreement emerges from the comment that Holloway "... uses an idiosyncratic definition of the relevant objective function of the government (Alston, Smith, and Vercammen, p. 543, paragraph 2)." The objective function that generates equations (1) and (2) (see the Appendix) is the same as the objective function used by Gardner (1995) when he first questioned Alston, Carter, and Smith's claim that a "domestic distortion can make a border intervention efficient in transferring surplus from consumers and taxpayers to farmers." The objective function used by Gardner (1995) is the same objective function used in the contributions that precede it and thus defines the literature on the debate about borderversus- domestic intervention (Streeten; Yeh; Paarlberg 1984, 1985; Orden; Gardner 1985). The objective function in the latter literature is the same as the one implied in another literature that originates from Wallace and includes most notably Gardner (1983), but also Alston and Hurd. Amer. J. Agr. Econ. 86(2) (May 2004): 549-552 Copyright 2004 American Agricultural Economics Association This content downloaded on Tue, 15 Jan 2013 07:58:41 AM All use subject to JSTOR Terms and Conditions 550 May 2004 Amer. J. Agr. Econ. The objective function in Holloway is this same objective function-it is, of course, Marshallian surplus.1 The third disagreement concerns scholarship. The Comment does not seem to be cognizant of several important papers, especially Bhagwati and Ramaswami, and Bhagwati, both of which precede Corden (1974, 1997); but also Lipsey and Lancaster, and Moschini and Sckokai; one important aspect of Alston and Hurd; and one extremely important result in Holloway. This oversight has some unfortunate repercussions. First, it misdirects to the wrong origins of intellectual property. Second, it misleads about the appropriateness of some welfare calculations. Third, it prevents Alston, Smith, and Vercammen from linking a finding in Holloway (pp. 242-43) with an old theorem (Lipsey and Lancaster) that settles the controversy (Alston, Carter, and Smith 1993, 1995; Gardner 1995; and, presently, Alston, Smith, and Vercammen) about the efficiency of border intervention in the presence of domestic distortions.

From ensemble forecasts to predictive distribution functions

The translation of an ensemble of model runs into a probability distribution is a common task in model-based prediction. Common methods for such ensemble interpretations proceed as if verification and ensemble were draws from the same underlying distribution, an assumption not viable for most, if any, real world ensembles. An alternative is to consider an ensemble as merely a source of information rather than the possible scenarios of reality. This approach, which looks for maps between ensembles and probabilistic distributions, is investigated and extended. Common methods are revisited, and an improvement to standard kernel dressing, called ‘affine kernel dressing’ (AKD), is introduced. AKD assumes an affine mapping between ensemble and verification, typically not acting on individual ensemble members but on the entire ensemble as a whole, the parameters of this mapping are determined in parallel with the other dressing parameters, including a weight assigned to the unconditioned (climatological) distribution. These amendments to standard kernel dressing, albeit simple, can improve performance significantly and are shown to be appropriate for both overdispersive and underdispersive ensembles, unlike standard kernel dressing which exacerbates over dispersion. Studies are presented using operational numerical weather predictions for two locations and data from the Lorenz63 system, demonstrating both effectiveness given operational constraints and statistical significance given a large sample.

Can adherence to dietary guidelines address excess caloric intake? An empirical assessment for the UK

The facilitation of healthier dietary choices by consumers is a key element of government strategies to combat the rising incidence of obesity in developed and developing countries. Public health campaigns to promote healthier eating often target compliance with recommended dietary guidelines for consumption of individual nutrients such as fats and added sugars. This paper examines the association between improved compliance with dietary guidelines for individual nutrients and excess calorie intake, the most proximate determinant of obesity risk. We apply quantile regressions and counterfactual decompositions to cross-sectional data from the National Diet and Nutrition Survey (2000-01) to assess how excess calorie consumption patterns in the UK are likely to change with improved compliance with dietary guidelines. We find that the effects of compliance vary significantly across different quantiles of calorie consumption. Our results show that compliance with dietary guidelines for individual nutrients, even if successfully achieved, is likely to be associated with only modest shifts in excess calorie consumption patterns. Consequently, public health campaigns that target compliance with dietary guidelines for specific nutrients in isolation are unlikely to have a significant effect on the obesity risk faced by the population.