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Number of results: 11
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Abstract

In this paper, the stock price-inflation nexus is investigated using the tools of wavelet power spectrum, cross-wavelet power spectrum and cross-wavelet coherency to unravel time and frequency dependent relationships between stock prices and inflation. Our results suggest that for a frequency band between sixteen and thirty two months, there is some evidence of the fisher effect. For rest of the frequencies and time periods however there is no evidence of the fisher effect and it seems stock prices have not played any role as an inflation hedge.

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Authors and Affiliations

Niyati Bhanja
Arif Billah Dar
Aviral Kumar Tiwari
Olaolu Richard Olayeni
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Abstract

Often daily prices on different markets are not all observable. The question is whether we should exclude from modelling the days with prices not available on all markets (thus loosing some information and implicitly modifying the time axis) or somehow complete the missing (non-existing) prices. In order to compare the effects of each of two ways of dealing with partly available data, one should consider formal procedures of replacing the unavailable prices by their appropriate predictions. We propose a fully Bayesian approach, which amounts to obtaining the marginal posterior (or predictive) distribution for any particular day in question. This procedure takes into account uncertainty on missing prices and can be used to check validity of informal ways of ”completing” the data (e.g. linear interpolation). We use the MSF-SBEKK structure, the simplest among hybrid MSV-MGARCH models, which can parsimoniously describe volatility of a large number of prices or indices. In order to conduct Bayesian inference, the conditional posterior distributions for all unknown quantities are derived and the Gibbs sampler (with Metropolis-Hastings steps) is designed. Our approach is applied to daily prices from six different financial and commodity markets; the data cover the period from December 21, 2005 till September 30, 2011, so the time of the global financial crisis is included. We compare inferences (on individual parameters, conditional correlation coefficients and volatilities), obtained in the cases where incomplete observations are either deleted or forecasted.

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Authors and Affiliations

Krzysztof Osiewalski
Jacek Osiewalski
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Abstract

This paper discusses the challenges faced by the empirical macroeconomist and methods for surmounting them. These challenges arise due to the fact that macroeconometric models potentially include a large number of variables and allow for time variation in parameters. These considerations lead to models which have a large number of parameters to estimate relative to the number of observations. A wide range of approaches are surveyed which aim to overcome the resulting problems. We stress the related themes of prior shrinkage, model averaging and model selection. Subsequently, we consider a particular modelling approach in detail. This involves the use of dynamic model selection methods with large TVP-VARs. A forecasting exercise involving a large US macroeconomic data set illustrates the practicality and empirical success of our approach.

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Authors and Affiliations

Gary Koop
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Abstract

The research into the use of less costly modifications of road links and networks, and changes in the service of road surroundings aimed at ensuring an improvement of through traffic performance in suburban areas, and on roads passing through built-up areas as small localities, with application of simulation model, is presented in this paper. From among possible designs, the authors investigated and presented the effectiveness of two, i.e. implementation of an additional multifunctional median lane in the road cross-section, and construction of service roads with different locations of intersections (end or middle of the road section).

The analysis is focused on the impact of such changes on traffic performance and road safety. The authors analysed travel speed, delay and share of platoon traffic on a uniform sections of the road for different types of road surroundings service. The study presents the results of analyses of road network before and after modification, and the assessment of:

•impact of access points density and level of their use on road traffic performance,
•impact of driving through road sections in built-up area on building platoon traffic,
•impact of change in the cross-section type on traffic performance.

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Authors and Affiliations

M. Kieć
M. Tracz
S. Gaca
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Abstract

The paper presents achievements in gluing technique in steel and aluminium structures. Adhesives currently in use and available on the market are characterized from the point of view of their mechanical properties. Design rules of adhesive connections and basic methods for their calculations are mentioned. The most significant examples of the applications of those joints in steel as well as aluminium structures are shown.

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Authors and Affiliations

M. Piekarczyk
R. Grec
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Abstract

Reinforced concrete composite slab consists of a thin prefabricated slab in which span reinforcement is located and of concrete joined with the slab, with such concrete being laid on site.

The existence of a joint of two concretes in such floors is interpreted as introducing a contact layer into a monolithic slab. In the paper parameters of two models are estimated. The first is a model of a contact layer and the second is a model of a composite slab with a single degree of freedom. The models consider that the contact has elastic properties and inelastic properties causing energy dissipation. Experimental investigations are discussed further based on which the parameters values of the contact layer model were determined.

Delamination was experienced for the slabs characterised by low contact layer stiffness after applying a maximum load. In addition, the strains of a contact layer having low stiffness are accompanied by lower energy dissipation than of a layer with high stiffness.

The smaller stiffness of composite floors, as compared to monolithic floors, occurs as a consequence of the existence of a joint. Such decrease for a composite slab is interpreted in the model with a single degree of freedom as the serial connection of stiffness of a monolithic slab and an element considering the existence of a contact layer.

The stiffness of an element considering the existence of a contact layer decreases along with a load, and the elements corresponding to the higher stiffness of the contact layer are characterised by higher energy dissipation.

The aforementioned results of the investigations confirm the assumptions of the contact layer model and a composite slab model with a single degree of freedom. The findings made represent a basis for establishing a method of evaluating the condition of a joint in composite slabs according to statistical investigations.

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K. Gromysz
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Abstract

The paper discusses the influence of the initial parameters on the strength parameters of S235JR steel at low stress triaxiality. The analysis was performed using the Gurson-Tvergaard-Needlem (GTN) material model, which takes into consideration the material structure. The initial material porosity was defined as the void volume fraction f₀. The fully dense material without pores was assumed and the typical and maximum values of porosity were considered for S235JR steel in order to analyse the porosity effect. The strength analysis of S235JR steel was performed basing on the force-elongation curves obtained experimentally and during numerical simulations. Taking into consideration the results obtained, the average values of the initial void volume fraction f₀ = 0.001 for S235JR steel is recommended to use in a common engineering calculations for elements operating at low stress triaxiality. In order to obtain more conservative results, the maximum values of f₀ = 0.0024 may be used.

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P.G. Kossakowski
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Abstract

The use of shredded tyre in civil engineering applications is a significant potential end use market. The reuse of tyre chips may not only address growing environmental and economic concerns, but also help to solve geotechnical problems associated with low shear strength. The purpose of this paper is to investigate the properties of tyre chips and tyre chips – sand mixture, and to find the mixture with the highest shear strength. In this study, an experimental testing program was undertaken using a large – scale triaxial apparatus with the goal of evaluating the optimum percentage of tyre chips in sand. The effects on shear strength of varying percentage of tyre chips and varying confining pressure were studied. Tyre chips content was suspected to have influence on stress – strain and volumetric strain behaviour of the mixture. Some tests were conducted to check the influence of number of used membranes, of saturation and compaction, on sample properties.

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Authors and Affiliations

E. Dembicki
M. Kowalczyk
P. Gotteland
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Abstract

This paper presents numerical two-dimensional results for fine-grained concrete under quasi-static three-point bending at meso-scale. Concrete was modelled as a random heterogeneous three-phase material. The simulations for notched concrete beams were carried out with the standard finite element method using an isotropic damage constitutive model enhanced by a characteristic length of micro-structure by means of a non-local theory. The effect of the volume fraction, shape, size, statistical distribution and stiffness of aggregate was analysed. Moreover, the effect of the bond thickness, notch size and characteristic length of micro-structure on the material behaviour was numerically investigated. The FE results were compared with own laboratory test results and other meso-scale calculations for three-phase concrete elements.

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Authors and Affiliations

Ł. Skarżyński
J. Tejchman
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Abstract

Rapid Visual Screening (RVS) method for buildings was originally developed by the Applied Technology Council (ATC) in the late 1980’s for potential seismic hazards. This is a simple and almost a quick way of assessing the building seismic vulnerability score based on visual screening. The logarithmic relationship between final score and the probability of collapse at the maximum considered earthquake (MCE) makes results somewhat difficult to interpret, especially for less technical users. This study is developed to improve the simplicity and usefulness of RVS methodology to determine the numeric scores for seismic vulnerability of buildings using vulnerability functional form. The proposed approach applies the existing method in FEMA 154 (2002) for calculating the building rank based on RVS method. In this study RVS scores are used to evaluate populations of buildings to prioritize detailed evaluations and seismic retrofits. The alternate non-logarithmic format of scoring scheme is much better meeting the needs of the project managers and decision makers, as they require results that are easier to understand. It shows the linear equivalent of RVS final scores which is consistent with the existing ranking systems used in the buildings management program such as budget allocation decision making. The results demonstrate that the weight determined for the factor of “Region Seismicity”, which is 0.4033, has the highest contribution to seismic vulnerability scores of buildings. The applicability of the proposed method is demonstrated through a hypothetical example to rank ten seismically vulnerable buildings.

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Authors and Affiliations

Mohammadreza Yadollahi
Azlan Adnan
Rosli Mohamad Zin

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