The marginal likelihood of Structural Time Series Models, with application to the euroareaa nd US NAIRU

We propose a simple procedure for evaluating the marginal likelihood in univariate Structural Time Series (STS) models. For this we exploit the statistical properties of STS models and the results in Dickey (1968) to obtain the likelihood function marginally to the variance parameters. This strategy applies under normal-inverted gamma-2 prior distributions for the structural shocks and associated variances. For trend plus noise models such as the local level and the local linear trend, it yields the marginal likelihood by simple or double integration over the (0,1)-support. For trend plus cycle models, we show that marginalizing out the variance parameters greatly improves the accuracy of the Laplace method. We apply this ethodology to the analysis of US and euro area NAIRU.Marginal likelihood, Markov Chain Monte Carlo, unobserved components, bridge sampling, Laplace method, NAIRU

Microfluidics for simultaneous quantification of platelet adhesion and blood viscosity

Platelet functions, including adhesion, activation, and aggregation have an influence on thrombosis and the progression of atherosclerosis. In the present study, a new microfluidic-based method is proposed to estimate platelet adhesion and blood viscosity simultaneously. Blood sample flows into an H-shaped microfluidic device with a peristaltic pump. Since platelet aggregation may be initiated by the compression of rotors inside the peristaltic pump, platelet aggregates may adhere to the H-shaped channel. Through correlation mapping, which visualizes decorrelation of the streaming blood flow, the area of adhered platelets (A(Platelet)) can be estimated without labeling platelets. The platelet function is estimated by determining the representative index I-A.T based on A(Platelet) and contact time. Blood viscosity is measured by monitoring the flow conditions in the one side channel of the H-shaped device. Based on the relation between interfacial width (W) and pressure ratio of sample flows to the reference, blood sample viscosity (mu) can be estimated by measuring W. Biophysical parameters (IA.T, mu) are compared for normal and diabetic rats using an ex vivo extracorporeal model. This microfluidic-based method can be used for evaluating variations in the platelet adhesion and blood viscosity of animal models with cardiovascular diseases under ex vivo conditions.119Ysciescopu

A constraint-stabilized time-stepping approach for piecewise smooth multibody dynamics

Rigid multibody dynamics is an important area of mathematical modeling which attempts to predict the position and velocity of a system of rigid bodies. Many methods will use smooth bodies without friction. The task is made especially more difficult in the face of noninterpenetration constraints, joint constraints, and friction forces. The difficulty that arises when noninterpenetration constraints are enforced is directly related to the fact that the usual methods of computing the distance between bodies do not give any indication of the amount of penetration when two bodies interpenetrate. Because we wish to calculate vectors that are normal to contact, and because it is necessary to determine the amount of penetration, when it exists, the classical computation of the depth of penetration when applied to convex polyhedral bodies is inefficient.We hereby describe a new method of determining when two convex polyhedra intersect and of evaluating a measure of the amount of penetration, when it exists. Our method is much more efficient than the classic computation of the penetration depth since it can be shown that its complexity grows only linearly with the size of the problem. We use our method to construct a signed distance function and implement it for use with a method for achieving geometrical constraint stabilization for a linear-complementarity-based time-stepping scheme for rigid multibody dynamics with joints, contact, and friction which, before now, was not equipped to handle polyhedral bodies. During our analysis, we describe how to compute normal vectors at contact, despite the cases when the classic derivative fails to exist.We put this analysis into a time-stepping procedure that uses a convex relaxation of a mixed linear complementarity problem with a resulting fixed point iteration that is guaranteed to converge if the friction is not too large, the time step is not too large, and the initial solution is feasible. Finally, we construct an algorithm that achieves constraint stabilization with quadratic convergence.The numerical results proved to be quite satisfactory, implying that the constraint stabilization holds, and that quadratic convergence exists

Wind Loading Analysis of Standing Seam Metal Roofs on Low-Rise Buildings

Standing seam metal roofs (SSMR) are a roofing system made up of prefabricated panels secured to the underlying structural purlins using concealed clips. The present study sought to develop a simplified code-approach for evaluating SSMRs. A model of the wind field and wind loads was validated using wind tunnel data from Arif (2017), influence functions and clip layout from Xia (2022), and compared the results to ASCE 7-22. Worst case enveloped GCp were compared by area for three different models: (i) ASCE Method, which gives wind loads based on bare deck roof, (ii) Clip Tributary Area (CTA) Method, which assumed the SSMR configuration and the clip geometric tributary area to predict clip loads, and (iii) Influence Function (IF) Method, which assumed the SSMR configuration and influence functions to determine clip loads. A load adjustment factor was calculated to compare the pressure coefficients between the ASCE Method and IF Method, this quantified the difference between the code model and a model that considered load sharing. The ASCE Method produced results that followed normal building aerodynamics, showing as effective wind area size increases the peak pressure decreases. The CTA Method significantly overestimated the ridge clip and eave clip loads compared to the IF Method. Typically, a roof on a low-rise building experiences the highest suction at the corners and edges. These areas coincide with the clips that have the greatest load sharing, and thus, the peak suction was reduced in these regions. Predicted clip loads from the CTA Method and IF Method did not show correlation with area. The ASCE Method was compared to the IF Method and the proposed load adjustment factor was presented for each ASCE zone and for inner clips and ridge and eave clips separately. The load adjustment factor indicates the ASCE Method is generally 8-59% conservative in its predictions

動画対応フラットパネルディテクタによる肺機能画像診断法 : 肺シンチグラフィ所見との比較

金沢大学医薬保健研究域保健学系Pulmonary ventilation and circulation dynamics are reflected on dynamic chest radiographs as changes in X-ray translucency,i.e., pixel values. The present study was performed to develop a pulmonary functional evaluation method based on the changes in pixel value, and to investigate the clinical usefulness of our method. Sequential chest radiographs of 20 subjects (abnormal,n=12; normal,n=8) during respiration were obtained with a dynamic flat-panel detector (FPD) system. The average pixel value in each local area was measured tracking the same area. To facilitate visual evaluation, the results were mapped on the original image using a grayscale in which small changes were shown in black and large changes were shown in white. In our clinical evaluation in comparison with a pulmonary scintigraphy, pulmonary ventilation disorder was indicated as a reduction of changes in pixel values. In many patients, there was a correlation between our result and a pulmonary scintigraphy (0.7<r, 4 cases; 0.4<r<or=0.7, 6 cases; 0.2<r<or=0.4, 1 case; 0<r<or=0.2, 1 case). The present method with real-time computer analysis is expected to be a rapid and simple method for evaluating pulmonary function and as an additional examination in conventional chest radiography

Efficient method for probabilistic fire safety engineering

A growing interest exists within the fire safety community for the topics of risk and reliability. However, due to the high computational requirements of most calculation models, traditional Monte Carlo methods are in general too time consuming for practical applications. In this paper a computationally very efficient methodology is for the first time applied to structural fire safety. The methodology allows estimating the probability density function which describes the uncertain response of the fire exposed structure or structural member, while requiring only a very limited number of model evaluations. The application of the method to structural fire safety is illustrated by two examples in the area of concrete elements exposed to fire

Vocal Fold Analysis From High Speed Videoendoscopic Data

High speed videoendoscopy (HSV) of the larynx far surpasses the limits of videostroboscopy in evaluating the vocal fold vibratory behavior by providing much higher frame rate. HSV enables the visualization of vocal fold vibratory pattern within an actual glottic cycle. This very detailed infor-mation on vocal fold vibratory characteristics could provide valuable information for the assessment of vocal fold vibratory function in disordered voices and the treatments effects of the behavioral, medical and surgical treatment procedures. In this work, we aim at addressing the problem of classi-fying voice disorders with varying etiology by following four steps described shortly. Our method-ology starts with glottis segmentation. Given a HSV data, the contour of the glottal opening area in each frame should be acquired. These contours record the vibration track of the vocal fold. After this, we obtain a reliable glottal axis that is necessary for getting certain vibratory features. The third step is the feature extraction on HSV data. In the last step, we complete the classification based on the features obtained from step 3. In this study, we first propose a novel glottis segmentation method based on simplified dynam-ic programming, which proves to be efficient and accurate. In addition, we introduce a new ap-proach for calculating the glottal axis. By comparing the proposed glottal axis determination meth-ods (modified linear regression) against state-of-the-art techniques, we demonstrate that our tech-nique is more reliable. After that, the concentration shifts to feature extraction and classification schemes. Eighteen different features are extracted and their discrimination is evaluated based on principal component analysis. Support vector machine and neural network are implemented to achieve the classification among three different types of vocal folds(normal vocal fold, unilateral vocal fold polyp, and unilateral vocal fold paralysis). The result demonstrates that the classification rates of four different tasks are all above 80%