37,970 research outputs found
Mathematical Relationships Between Two Sets of Laser Anemometer Measurements for Resolving the Total Velocity Vector
The mathematical relations between the measured velocity fields for the same compressor rotor flow field resolved by two fringe type laser anemometers at different observational locations are developed in this report. The relations allow the two sets of velocity measurements to be combined to produce a total velocity vector field for the compressor rotor. This report presents the derivation of the mathematical relations, beginning with the specification of the coordinate systems and the velocity projections in those coordinate systems. The vector projections are then transformed into a common coordinate system. The transformed vector coordinates are then combined to determine the total velocity vector. A numerical example showing the solution procedure is included
Development expenditures and the local financing constraint
Focusing on the local financing constraint sheds new light on issues of aid, fiscal reform, and the management of public spending. The fungibility of aid need not translate into resource flows to fill the local financing gap. Indeed, project aid can widen the local financing gap. To augment direct local financing of development, aid must be nonproject aid that can generate local currency. In the longer term, project aid's effect on local financing lies in its impact on growth and on expanding the base for tax revenues, seigniorage, and borrowing. When inadequate local financing limits project implementation and effective use of aid, local currency funds are more valuable than project aid, at the margin--and it becomes important to reallocate local funds, to leverage project aid, and to raise the quality of investment projects. A persistent gap in local financing complicates programs of fiscal reform. For such programs to be effective, the local financing gap has to be confronted directly by matching planned local fund expenditures against expected local fund receipts. This requires a transparent database to develop indicators and to monitor the allocation and use of local resources.Development Economics&Aid Effectiveness,Economic Theory&Research,Environmental Economics&Policies,Payment Systems&Infrastructure,Fiscal&Monetary Policy,Environmental Economics&Policies,Development Economics&Aid Effectiveness,National Governance,Fiscal&Monetary Policy,Economic Theory&Research
A Multivariate GARCH Model with Time-Varying correlations
In this paper we propose a new multivariate GARCH model with time- varying correlations. We adopt the vech representation based on the conditional variances and the conditional correlations. While each conditional-variance term is assumed to follow a univariate GARCH formulation, the conditional-correlation matrix is postulated to follow an autoregressive moving average type of analogue. By imposing some suitable restrictions on the conditional-correlation-matrix equation, we construct a MGARCH model in which the conditional-correlation matrix is guaranteed to be positive definite during the optimisation. Thus, our new model retains the intuition and interpretation of the univariate GARCH model and yet satisfies the positive-definite condition as found in the constant-correlation and BEKK models. We report some Monte Carlo results on the finite-sample distributions of the MLE of the varying- correlation MGARCH model. The new model is applied to some real data sets. It is found that extending the constant-correlation model to allow for time-varying correlations provides some interesting time histories that are not available in a constant-correlation model.BEKK model, constant correlation, Monte Carlo method, multivariate GARCH model, maximum likelihood estimate, varying correlation
Time-Varying Currency Betas: Evidence from Developed and Emerging Markets
This paper examines the conditional time-varying currency betas from five developed markets and four emerging markets. A trivariate BEKK-GARCH-in-mean model is used to estimate the timevarying conditional variance and covariance of returns of stock index, the world market portfolio and changes in bilateral exchange rate between the US dollar and the local currency of each country. It is found that currency betas are more volatile than those of the world market betas. Currency betas in emerging markets are more volatile than those in developed markets. Moreover, we find evidence of long-memory in currency betas. The usefulness of time-varying currency betas are illustrated by two applications.time-varying currency betas; multivariate GARCH-M models; international CAPM; fractionally integrated processes; stochastic dominance
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