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1.
Anti-reflective (AR) boundary conditions (BC) have been introduced recently in connection with fast deblurring algorithms, both in the case of signals and images. Here we extend such BCs to d dimensions (d ≥ 1) and we study in detail the algebra induced by the AR-BCs, with strongly symmetric point spread functions (PSF), both from a structural and computational point of view. The use of the re-blurring idea and the computational features of the AR-algebra allow us to apply Tikhonov-like techniques within O(n d log(n)) arithmetic operations, where n d is the number of pixels of the reconstructed object. Extensive numerical experimentation concerning 2D images and strongly symmetric PSFs confirms the effectiveness of our proposal.   相似文献   
2.
Sensitivity analysis studies how the variation in model outputs can be due to different sources of variation. This issue is addressed, in this study, as an application of sensitivity analysis techniques to a crop model in the Mediterranean region. In particular, an application of Morris and Sobol' sensitivity analysis methods to the rice model WARM is presented. The output considered is aboveground biomass at maturity, simulated at five rice districts of different countries (France, Greece, Italy, Portugal, and Spain) for years characterized by low, intermediate, and high continentality. The total effect index of Sobol' (that accounts for the total contribution to the output variation due a given parameter) and two Morris indices (mean μ and standard deviation σ of the ratios output changes/parameter variations) were used as sensitivity metrics. Radiation use efficiency (RUE), optimum temperature (Topt), and leaf area index at emergence (LAIini) ranked in most of the combinations site × year as first, second and third most relevant parameters. Exceptions were observed, depending on the sensitivity method (e.g. LAIini resulted not relevant by the Morris method), or site-continentality pattern (e.g. with intermediate continentality in Spain, LAIini and Topt were second and third ranked; with low continentality in Portugal, RUE was outranked by Topt). Low σ values associated with the most relevant parameters indicated limited parameter interactions. The importance of sensitivity analyses by exploring site × climate combinations is discussed as pre-requisite to evaluate either novel crop-modelling approaches or the application of known modelling solutions to conditions not explored previously. The need of developing tools for sensitivity analysis within the modelling environment is also emphasized.  相似文献   
3.
Markov chains are a well-known stochastic process that provide a balance between being able to adequately model the system's behavior and being able to afford the cost of the model solution. The definition of stochastic temporal logics like continuous stochastic logic (CSL) and its variant asCSL, and of their model-checking algorithms, allows a unified approach to the verification of systems, allowing the mix of performance evaluation and probabilistic verification. In this paper we present the stochastic logic CSLTA, which is more expressive than CSL and asCSL, and in which properties can be specified using automata (more precisely, timed automata with a single clock). The extension with respect to expressiveness allows the specification of properties referring to the probability of a finite sequence of timed events. A typical example is the responsiveness property "with probability at least 0.75, a message sent at time 0 by a system A will be received before time 5 by system B and the acknowledgment will be back at A before time 7", a property that cannot be expressed in either CSL or asCSL. We also present a model-checking algorithm for CSLTA.  相似文献   
4.
Equivalence relations can be used to reduce the state space of a system model, thereby permitting more efficient analysis. We study backward stochastic bisimulation in the context of model checking continuous-time Markov chains against continuous stochastic logic (CSL) properties. While there are simple CSL properties that are not preserved when reducing the state space of a continuous-time Markov chain using backward stochastic bisimulation, we show that the equivalence can nevertheless be used in the verification of a practically significant class of CSL properties. We consider an extension of these results to Markov reward models and continuous stochastic reward logic. Furthermore, we identify the logical properties for which the requirement on the equality of state-labeling sets (normally imposed on state equivalences in a model-checking context) can be omitted from the definition of the equivalence, resulting in a better state-space reduction  相似文献   
5.
This study expands and updates through 1995 our earlier report on influenza vaccine use in 18 developed countries. Five of the six countries with high levels of vaccine use in 1992 (> or = 130 doses/1000 population) showed little change or slight declines over the subsequent 3 years. The exception was the United States, where a new federal program for vaccination reimbursement for the elderly helped to increase vaccine distribution from 144 to 239 doses/1000 population. The six countries with medium levels of vaccine use in 1992 (76-96 doses/1000 population) increased to > or = 100 doses/1000 population by 1995. Among the six low-use countries in 1992 (< or = 65 doses/1000 population), only Finland showed substantial improvement (96 doses/1000 population) in 1995. Four new countries were added to the study. In Germany, vaccine use increased to 80 doses/1000 population in 1995, but in Ireland it remained at a low level (48 doses/1000 population). In Korea, vaccine use increased from 17 to 95 doses/ 1000 population during the period 1987-1995. In Japan, very high levels of vaccine use (approximately 280 doses/1000 population) in the early 1980s were associated with vaccination programs for school children. However, vaccine use fell precipitously when these programs were discontinued, and only 2 and 8 doses/1000 population were used in 1994 and 1995, respectively. In all 22 countries, higher levels of vaccine use were associated with vaccination reimbursement programs under national or social health insurance and were not correlated with different levels of economic development. Excluding Japan, in 1995 there was still a greater than fourfold difference between the highest and lowest levels of vaccine use among the other 21 countries in the study. Given its well established clinical effectiveness and cost-effectiveness, none of these countries has yet achieved the full benefits of its programs for influenza vaccination.  相似文献   
6.
The C-terminal aminoacidic sequence from NPM1-mutated protein, absent in normal human tissues, may serve as a leukemia-specific antigen and can be considered an ideal target for NPM1-mutated acute myeloid leukemia (AML) immunotherapy. Different in silico instruments and in vitro/ex vivo immunological platforms have identified the most immunogenic epitopes from NPM1-mutated protein. Spontaneous development of endogenous NPM1-mutated-specific cytotoxic T cells has been observed in patients, potentially contributing to remission maintenance and prolonged survival. Genetically engineered T cells, namely CAR-T or TCR-transduced T cells, directed against NPM1-mutated peptides bound to HLA could prospectively represent a promising therapeutic approach. Although either adoptive or vaccine-based immunotherapies are unlikely to be highly effective in patients with full-blown leukemia, these strategies, potentially in combination with immune-checkpoint inhibitors, could be promising in maintaining remission or preemptively eradicating persistent measurable residual disease, mainly in patients ineligible for allogeneic hematopoietic stem cell transplant (HSCT). Alternatively, neoantigen-specific donor lymphocyte infusion derived from healthy donors and targeting NPM1-mutated protein to selectively elicit graft-versus-leukemia effect may represent an attractive option in subjects experiencing post-HSCT relapse. Future studies are warranted to further investigate dynamics of NPM1-mutated-specific immunity and explore whether novel individualized immunotherapies may have potential clinical utility in NPM1-mutated AML patients.  相似文献   
7.
Asynchronously communicating stochastic modules (SAM) are Petri nets that can be seen as a set of modules that communicate through buffers, so they are not (yet another) Petri net subclass, but they complement a net with a structured view. This paper considers the problem of exploiting the compositionality of the view to generate the state space and to find the steady-state probabilities of a stochastic extension of SAM in a net-driven, efficient way. Essentially we give an expression of an auxiliary matrix, G, which is a supermatrix of the infinitesimal generator of a SAM. G is a tensor algebra expression of matrices of the size of the components for which it is possible to numerically solve the characteristic steady-state solution equation π·G=0, without the need to explicitly compute G. Therefore, we obtain a method that computes the steady-state solution of a SAM without ever explicitly computing and storing its infinitesimal generator, and therefore without computing and storing the reachability graph of the system. Some examples of application of the technique are presented and compared to previous approaches  相似文献   
8.
The melting behavior of physical blends prepared from low, medium, and high density polyethylene was examined by differential scanning calorimetry. Binary low/high and ternary low/medium/high density polyethylene blends showed two endothermic peaks which were attributed to the melting of the lower and higher density components. The percent crystallinity of the blends was calculated according to an additivity relationship using the crystallinity of the pure components. These results compared favorably with an experimental crystallinity measured from the area under the melting curves.  相似文献   
9.
International Journal on Software Tools for Technology Transfer - Decision diagrams (DDs) are widely used in system verification to compute and store the state space of finite discrete events...  相似文献   
10.
Lucy–Richardson (LR) is a classical iterative regularization method largely used for the restoration of nonnegative solutions. LR finds applications in many physical problems, such as for the inversion of light scattering data. In these problems, there is often additional information on the true solution that is usually ignored by many restoration methods because the related measurable quantities are likely to be affected by non-negligible noise. In this article we propose a novel Weakly Constrained Lucy–Richardson (WCLR) method which adds a weak constraint to the classical LR by introducing a penalization term, whose strength can be varied over a very large range. The WCLR method is simple and robust as the standard LR, but offers the great advantage of widely stretching the domain range over which the solution can be reliably recovered. Some selected numerical examples prove the performances of the proposed algorithm.  相似文献   
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