An unsupervised acoustic fall detection system using source separation for sound interference suppression

We present a novel unsupervised fall detection system that employs the collected acoustic signals (footstep sound signals) from an elderly person׳s normal activities to construct a data description model to distinguish falls from non-falls. The measured acoustic signals are initially processed with a source separation (SS) technique to remove the possible interferences from other background sound sources. Mel-frequency cepstral coefficient (MFCC) features are next extracted from the processed signals and used to construct a data description model based on a one class support vector machine (OCSVM) method, which is finally applied to distinguish fall from non-fall sounds. Experiments on a recorded dataset confirm that our proposed fall detection system can achieve better performance, especially with high level of interference from other sound sources, as compared with existing single microphone based methods

Word Searching in Scene Image and Video Frame in Multi-Script Scenario using Dynamic Shape Coding

Retrieval of text information from natural scene images and video frames is a challenging task due to its inherent problems like complex character shapes, low resolution, background noise, etc. Available OCR systems often fail to retrieve such information in scene/video frames. Keyword spotting, an alternative way to retrieve information, performs efficient text searching in such scenarios. However, current word spotting techniques in scene/video images are script-specific and they are mainly developed for Latin script. This paper presents a novel word spotting framework using dynamic shape coding for text retrieval in natural scene image and video frames. The framework is designed to search query keyword from multiple scripts with the help of on-the-fly script-wise keyword generation for the corresponding script. We have used a two-stage word spotting approach using Hidden Markov Model (HMM) to detect the translated keyword in a given text line by identifying the script of the line. A novel unsupervised dynamic shape coding based scheme has been used to group similar shape characters to avoid confusion and to improve text alignment. Next, the hypotheses locations are verified to improve retrieval performance. To evaluate the proposed system for searching keyword from natural scene image and video frames, we have considered two popular Indic scripts such as Bangla (Bengali) and Devanagari along with English. Inspired by the zone-wise recognition approach in Indic scripts[1], zone-wise text information has been used to improve the traditional word spotting performance in Indic scripts. For our experiment, a dataset consisting of images of different scenes and video frames of English, Bangla and Devanagari scripts were considered. The results obtained showed the effectiveness of our proposed word spotting approach.Comment: Multimedia Tools and Applications, Springe

MODELING EXCHANGE RATE VOLATILITIES IN CROATIA

Modeling and forecasting exchange rate volatility has important implications in a range of areas in macroeconomics and finance. A number of models have been developed in empirical finance literature to investigate this volatility across different regions and countries. Well known and frequently applied models to estimate exchange rate volatility are the autoregressive conditional heteroscedastic (ARCH) model advanced by Engle (1982) and the generalized (GARCH) model developed independently by Bollerslev (1986) and Taylor (1986). This paper examines the performance of several ARCH models for the EUR and USD against the HRK on daily data sets within the time period from 1997 to 2015. Evaluating the models through standard information criteria showed that the GARCH (2,1) is the best fitted model  for the EUR/HRK and the GARCH (1,1) for the USD/HRK daily return volatility. In accordance to the estimated models there is no empirical evidence that negative and positive shocks imply a different next period volatility of the daily EUR/HRK as well as the USD/HRK exchange rate return.</p

Integration of Different Constitutive Models in Multibody System Algorithms

Multibody systems (MBS) in general include two collections of bodies. One collection consists of bulky and compact solids which can be treated as rigid bodies, while the second collection includes bodies that can be treated as flexible bodies that experience small and large deformations and undergo large rotations. Many technological and industrial problems such as liquid sloshing, textile hyper-elastic, biomechanics and vehicle terrain interaction require efficient and accurate modeling of flexible bodies. One of the objectives of this thesis is to develop a low order continuum-based liquid sloshing model that can be successfully integrated with multibody system algorithms. The liquid sloshing model proposed in this thesis allows for capturing the effect of the distributed inertia and the viscosity of the fluid. The fluid viscous forces are defined using the Navier-Stokes equations. In order to demonstrate the use of the approach presented in this study, the assumption of an incompressible Newtonian fluid is considered with a total Lagrangian approach. Fluid properties such as the incompressibility condition are formulated using a penalty method. The low order model that could capture the effect of the distributed fluid inertia on the vehicle dynamics is developed in this thesis using the floating frame reference (FFR) formulation. The use of this approach allows for developing an inertia-variant fluid model that accounts for the dynamic coupling between different modes of the fluid displacements. The matrix of position vector gradients and its derivative are formulated using the FFR kinematic description. The position and velocity gradient tensors are used to define the Navier-Stokes stress forces. The proposed liquid sloshing model is integrated with a MBS railroad vehicle model in which the rail/wheel interaction is formulated using a three-dimensional elastic contact formulation that allows for the wheel/rail separation. Several simulation scenarios are used to examine the effect of the distributed liquid inertia on the motion of the railroad vehicle. The results, obtained using the sloshing model, are compared with the results obtained using a rigid body vehicle model. The comparative numerical study presented in this thesis shows that the effect of the sloshing tends to increase the possibility of wheel/rail separation as the forward velocity increases, thereby increasing the possibility of derailments at these relatively high speeds. Another objective of this thesis is to develop a total Lagrangian non-incremental liquid sloshing solution procedure based on the finite element (FE) absolute nodal coordinate formulation (ANCF). The proposed liquid sloshing modeling approach can be used to avoid the difficulties of integrating most of fluid dynamics formulations, which are based on the Eulerian approach, with MBS dynamics formulations, which are based on a total Lagrangian approach. The proposed total Lagrangian FE fluid dynamics formulation, which can be systematically integrated with computational MBS algorithms, differs significantly from the conventional FE or finite volume methods which are based on an Eulerian representation that employs the velocity field of a fixed control volume in the region of interest. The ANCF fluid equations are expressed in terms of displacement and gradient coordinates of material points, allowing for straight forward implementation of kinematic constraint equations and for the systematic modeling of the interaction of the fluid with the external environment or with rigid and flexible bodies. The fluid incompressibility conditions and surface traction forces are considered and derived directly from the Navier Stokes equations. Two ANCF brick elements, one of which is obtained using an incomplete polynomial representation and the other of which is obtained from a B-spline volume representation, are used. The new approach ensures the continuity of the displacement gradients at the nodal points and allows for imposing higher degree of continuity across the element interface by applying algebraic constraint equations that can be used to eliminate dependent variables and reduce the model dimensionality. Regardless of the magnitude of the fluid displacement, the fluid has a constant mass matrix, leading to zero Coriolis and centrifugal forces. The analysis presented in this thesis demonstrates the feasibility of developing an efficient non-incremental total Lagrangian approach for modeling sloshing problems in MBS system applications in which the bodies can experience large displacements including finite rotations. Several examples are presented in order to shed light on the potential of using the ANCF liquid sloshing formulation developed in this study. This thesis also presents a new flexible MBS approach for modeling textile systems including roll-drafting sets used in chemical textile machinery. The proposed approach can be used in the analysis of textile materials such as lubricated polyester filament bundles (PFB) which have un-common material properties best described by specialized continuum mechanics constitutive models. In this thesis, the ANCF is used to model PFB as a hyper-elastic transversely isotropic material. The PFB strain energy density function is decomposed into a fully isotropic component and an orthotropic, transversely isotropic component expressed in terms of five invariants of the right Cauchy-Green deformation tensor. Using this energy decomposition, the second Piola-Kirchhoff stress and the elasticity tensors can also be split into isotropic and transversely isotropic parts. The constitutive equations are used to define the generalized material forces associated with the coordinates of three-dimensional fully-parameterized ANCF finite elements. The proposed approach allows for modeling the dynamic interaction between the rollers polyester filament bundle and allows for using spline functions to describe the PFB forward velocity. The textile material constitutive equations and the MBS algorithms can be used effectively to obtain numerical solutions that define the state of strain and cross section deformation of the textile material and the relative slip and contact forces between rollers and PFB

Metallic Nanocages: Synthesis of Bimetallic Pt–Pd Hollow Nanoparticles with Dendritic Shells by Selective Chemical Etching

We report a facile synthesis of Pt–Pd bimetallic nanoparticles, named “metallic nanocages”, with a hollow interior and porous dendritic shell. This synthesis is easily achieved by selective chemical etching of Pd cores from dendritic Pt-on-Pd nanoparticles. The obtained Pt–Pd nanocages show superior catalytic activity for methanol oxidation reaction compared to other Pt-based materials reported previously

MOESM1 of 3C-digital PCR for quantification of chromatin interactions

Additional file 1: Table S1. Table of sequences of the primers and TaqMan probes used for dPCR

<b>The Ultimate Controlling Shareholder’s Motivation for Equity Pledge in China</b>

This paper empirically investigates the motivations of ultimate controlling shareholders’ equity pledges in the Chinese A-share market from two perspectives, financing constraints and interest encroachment, with a panel data regression model.</p

Uniformly Semiparametric Efficient Estimation of Treatment Effects With a Continuous Treatment

<p>This article studies identification, estimation, and inference of general unconditional treatment effects models with continuous treatment under the ignorability assumption. We show identification of the parameters of interest, the dose–response functions, under the assumption that selection to treatment is based on observables. We propose a semiparametric two-step estimator, and consider estimation of the dose–response functions through moment restriction models with generalized residual functions that are possibly nonsmooth. This general formulation includes average and quantile treatment effects as special cases. The asymptotic properties of the estimator are derived, namely, uniform consistency, weak convergence, and semiparametric efficiency. We also develop statistical inference procedures and establish the validity of a bootstrap approach to implement these methods in practice. Monte Carlo simulations show that the proposed methods have good finite sample properties. Finally, we apply the proposed methods to estimate the unconditional average and quantile effects of mothers’ weight gain and age on birthweight. Supplementary materials for this article are available online.</p

Photocatalyzed Facile Synthesis of α‑Chloro Aryl Ketones with Polyaniline–g‑C₃N₄–TiO₂ Composite under Visible Light

PANI (polyaniline)–g-C₃N₄–TiO₂ composite was prepared and utilized in the photocatalyzed synthesis of α-chloro aryl ketones via a radical-triggered domino process under oxygen atmosphere. This semiconductor photocatalyst showed good photocatalytic performance and chemoselectivity under visible light irradiation. A variety of aryl diazonium salts and aryl alkynes survived the reaction conditions well to afford the corresponding products in moderate to good yields. Scale-up (10 mmol) synthesis was also achieved. The recycle studies showed that the semiconductor composite could be readily recovered and reused for eight consecutive runs with a slight decrease in the catalytic activity. Control experiments were also performed, and a plausible catalytic mode was proposed

Additional file 3 of Targeting Bruton’s tyrosine kinase in vitreoretinal lymphoma: an open-label, prospective, single-center, phase 2 study

Additional file 3. Additional methods