Numerical Methods for Uncertainty Analysis in Dynamical Systems

The current methods for uncertainty analysis in dynamical systems are restricted in terms of computational cost and evaluation domain since they either use grid points or work only along trajectories. To break through these problems we present a new method: the Rothe & maximum-entropy method which follows the steps below. A deterministic dynamical system with initial value uncertainties can be analyzed via the uncertainty propagation which is based on the Liouville equation in the form of the first-order linear partial differential equation. On this equation we conduct a semi-discretization in time via A-stable rational approximations of consistency order k and this yields the stationary spatial problem. This spatial problem now can be solved by the spatial discretization scheme: we propose the maximum-entropy approximation which provides unbiased interpolations even with fewer numbers of scattered points. Through these steps we finally obtain a system of linear equations for the evolution of the probability density function ut, which can be easily solved in several ways. This method can provide more efficiency in terms of computation time thanks to using fewer numbers of scattered points instead of grid points. Also, it enables the constant tracking of probability density functions in a specific fixed domain of interest and this is especially effective for switched systems

Mean field elastic moduli of a three-dimensional cell-based vertex model

The mechanics of a foam typically depends on the bubble geometry, topology, and the material at hand, be it metallic or polymeric, for example. While the foam energy functional for each bubble is typically minimization of surface area for a given volume, biology provides us with a wealth of additional energy functionals, should one consider biological cells as a foam-like material. Here, we focus on a mean field approach to obtain the elastic moduli, within linear response, for an ordered, three-dimensional vertex model using the space-filling shape of a truncated octahedron and whose energy functional is characterized by a restoring surface area spring and a restoring volume spring. The tuning of the three-dimensional shape index exhibits a rigidity transition via a compatible-incompatible transition. Specifically, for smaller shape indices, both the target surface area and volume cannot be achieved, while beyond some critical value of the three-dimensional shape index, they can be, resulting in a zero-energy state. As the elastic moduli depend on curvatures of the energy when the system, we obtain these as well. In addition to analytically determining the location of the transition in mean field, we find that the rigidity transition and the elastic moduli depend on the parameterization of the cell shape with this effect being more pronounced in three dimensions given the array of shapes that a polyhedron can take on (as compared to a polygon). We also uncover nontrivial dependence on the deformation protocol in which some deformations result in affine motion of the vertices, while others result in nonaffine motion. Such dependencies on the shape parameterization and deformation protocol give rise to a nontrivial shape landscape and, therefore, nontrivial mechanical response even in the absence of topology changes.Comment: 18 pages, 24 figure

DR.CPO: Diversified and Realistic 3D Augmentation via Iterative Construction, Random Placement, and HPR Occlusion

In autonomous driving, data augmentation is commonly used for improving 3D object detection. The most basic methods include insertion of copied objects and rotation and scaling of the entire training frame. Numerous variants have been developed as well. The existing methods, however, are considerably limited when compared to the variety of the real world possibilities. In this work, we develop a diversified and realistic augmentation method that can flexibly construct a whole-body object, freely locate and rotate the object, and apply self-occlusion and external-occlusion accordingly. To improve the diversity of the whole-body object construction, we develop an iterative method that stochastically combines multiple objects observed from the real world into a single object. Unlike the existing augmentation methods, the constructed objects can be randomly located and rotated in the training frame because proper occlusions can be reflected to the whole-body objects in the final step. Finally, proper self-occlusion at each local object level and external-occlusion at the global frame level are applied using the Hidden Point Removal (HPR) algorithm that is computationally efficient. HPR is also used for adaptively controlling the point density of each object according to the object's distance from the LiDAR. Experiment results show that the proposed DR.CPO algorithm is data-efficient and model-agnostic without incurring any computational overhead. Also, DR.CPO can improve mAP performance by 2.08% when compared to the best 3D detection result known for KITTI dataset. The code is available at https://github.com/SNU-DRL/DRCPO.gi

Predictors of Upcycling in the Highly IndustrialisedWest: A Survey across Three Continents of Australia, Europe, and North America

open access articleUpcycling, as a way to reutilise resources, offers a promising alternative to production and consumption based on virgin materials. Despite the growing academic and industrial interest in recent years, there is a lack of large-scale cross-country or cross-regional studies that systematically investigate influencing factors for consumer upcycling behaviour. By drawing on social psychological theories of interpersonal behaviour and planned behaviour, this study investigated predictors of upcycling behaviour in five highly industrialised countries of three continents: Australia, Canada, Germany, UK, and USA. Results showed that intention and perceived behavioural control (confidence in abilities) were the most important factors for upcycling. Theoretical and practical implications from this study are discussed in the context of efforts to scale up global upcycling

Mutant pattern of p53 predicts local recurrence and poor survival rate in gastric cancer

Background. TP53 mutation is a poor prognostic factor for various organ malignancies such as colorectal cancer, breast cancer, ovarian cancer, hepatocellular carcinoma, lung adenocarcinoma and clinical pathologists previously evaluated it using immunohistochemistry for p53. The clinicopathologic significance of p53 expression in gastric cancer remains unclear due to inconsistent classification methods. Methods. Immunohistochemistry for p53 protein was performed using tissue microarray blocks generated from 725 cases of gastric cancer, and p53 expression was divided into three staining patterns using a semiquantitative ternary classifier: heterogeneous (wild type), overexpression, and absence (mutant pattern). Results. Mutant pattern of p53 expression had a male predominance, greater frequency in cardia/fundus, higher pT stage, frequent lymph node metastasis, local recurrence clinically, and more differentiated histology microscopically compared with wild type. In survival analysis, p53 mutant pattern was associated with worse recurrent-free survival and overall survival rates, and significance was maintained in subgroup analysis of early versus advanced gastric cancers. In Cox regression analysis, p53 mutant pattern was a significant predicting factor for local recurrence (relative risk (RR=4.882, p<0.001)) and overall survival (RR=2.040, p=0.007). The p53 mutant pattern remained significant for local recurrence (RR=2.934, p=0.018) in multivariate analyses. Conclusions. Mutant p53 pattern on immunohistochemistry was a significant prognostic factor for local recurrence and poor overall survival in gastric cancer

Serum 25-hydroxyvitamin D levels and risk of colorectal cancer:an age-stratified analysis

Background and aims: the role of circulating 25-hydroxyvitamin D (25(OH)D) in prevention of early-onset colorectal cancer (CRC) in young adults under 50 years is uncertain. We evaluated the age-stratified associations (&lt;50 vs. ≥50 years) :circulating 25(OH)D levels and the risk of CRC in a large sample of Korean adults.Methods: our cohort study included 236,382 participants (mean [standard deviation] age, 38.0 [9.0] years) who underwent a comprehensive health examination, including measurement of serum 25(OH)D levels. Serum 25(OH)D levels were categorized as follows: &lt;10, 10–20, and ≥20 ng/mL. CRC, along with the histologic subtype, site, and invasiveness was ascertained through linkage with the national cancer registry. Cox proportional hazard models were used to estimate hazard ratios (HRs; 95% confidence intervals [CIs]) for incident CRC according to the serum 25(OH)D status, with adjustment for potential confounders.Results: during the 1,393,741 person-years of follow-up (median, 6.5 years; interquartile range, 4.5–7.5 years), 341 participants developed CRC (incidence rate, 19.2 per 105 person-years). Among young individuals aged &lt;50 years, serum 25(OH)D levels were inversely associated with the risk of incident CRC with HRs (95% CIs) of 0.61 (0.43–0.86) and 0.41 (0.27–0.63) for 25(OH)D 10-19 and ≥20 ng/mL, respectively, with respect to the reference (&lt;10 ng/mL) (p for trend &lt;0.001, time-dependent model). Significant associations were evident for adenocarcinoma, colon cancer, and invasive cancers. For those aged ≥50 years, associations were similar, although slightly attenuated compared to younger individuals. Conclusions: serum 25(OH)D levels may have beneficial associations with the risk of developing CRC for both early-onset and late-onset disease. <br/

Thoracic Splenosis: A Case Report and the Importance of Clinical History

We present a case of thoracic splenosis in a 42-yr-old man with a medical history of abdominal surgery for a penetration injury with an iron bar of the left abdomen and back. He had been in good condition, but a chest radiograph taken during a regular checkup showed a multinodular left pleura-based mass. Computed tomography (CT) showed that the mass was well-enhanced and homogeneous, indicating a sclerosing hemangioma. Following its removal by video-assisted thoracoscopic surgery, the mass appeared similar to a hemangioma, with marked adhesion to the left side diaphragmatic pleura and lung parenchyma. Frozen section showed that the lesion was a solid mass consisted with abundant lymphoid cells, suggesting a low grade lymphoma. On permanent section, however, the mass was found to be composed of white pulp, red pulp, a thick capsule and trabeculae and was diagnosed as ectopic splenic tissue, or thoracic splenosis. Review of the patient's history and chest CT at admission revealed that the patient had undergone a splenectomy for the penetration injury 20 yr previously

Can Housing Bubbles persist under Normal Credit Conditions?

This paper analyzes house prices for a panel of 19 countries over a period of 21 years using broad categories of macroeconomic variables in order to detect possible bubble effects. The sample is divided into two sub-samples, one with normal credit conditions and one with abnormal credit conditions. “Normal” credit conditions are defined by the percentage of securitized mortgages in each country. The sub-sample with abnormal credit conditions are countries in which there are ex post confirmed housing bubbles, and the sub-sample with normal credit conditions are the countries in which we are testing for possible bubbles. The variance decompositions from Error Correction Vector Autoregressions (ECVAR) show that it is unlikely that the countries with normal credit conditions contain any significant bubble effects, from which we can generalize that it is difficult for housing bubbles to persist over long periods of time, under normal credit conditions