Department of Economics

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Resolving Land Use Conflicts
Tideman, Nicolaus (Farm Foundation, 1972)
Bearing estimation using a large towed array
Hinich, Melvin J.; Rule, William (Acoustical Society of America, 1975)
When a towed array of hydrophones is significantly nonlinear due to bending, ordinary linear array beamforming gives a biased estimate of the true source bearing. By processing the array as a sequence of smaller aperture subarrays and then computing the mean of the subarray bearings, the variation due to bending is reduced and a reasonably precise estimate is obtained if the average bending angle with respect to the nominal axis is small. The median and mean subarray bearings are analyzed for a theoreticalstatistical model and are tested using artificial data for various sinusoidal array geometries.
Bearing estimation using a perturbed linear array
Hinich, Melvin J. (Acoustical Society of America, 1977-06)
A linear hydrophone array which is towed in the ocean is subject to snakelike bending. If the array is processed as if it was truly linear, the author has shown that the bending causes a deflection of the measured bearing of a fixed source from its true bearing relative to the array. This deflection results from patterned perturbations in the true sensor positions along the nominal array axis. As the perturbation pattern changes with the flexing of the array, the source appears to move around. A probability model of the perturbations is used in order to develop a theoretical solution to the question of how the space-time information gathered by the array is best used to measure source bearing. The method which is used to reduce the bending perturbation deflection of the bearing is to group the sensors into adjacent subarrays, process these arrays over short time slices, average the subarray bearings for each time period, and then to average the average over time. This averaging method significantly improves the bearing accuracy of the source when the array is bent according to the model.
Demand for electricity in Virginia
Murray, M. P.; Spann, R.; Pulley, L.; Beauvais, E. (MIT Press, 1978)
Processing spatially aliased arrays
Hinich, Melvin J. (Acoustical Society of America, 1978-09)
A linear array can detect a plane wave signai at a wrong bearing if the signal wavelengths are shorter than twice the distance between the closest adjacent sensors. This penomenon, called spatial aliasing, is most pronounced when the bearing is near endfire. This paper presents a method for correcting spatial aliasing of broadband signals using the frequency-wavenumber approach to array processing. Also presented is a method for averaging the Fourier coefficients that will give a more accurate bearing estimator than the method presented by Clay, Hinich, and Shaman [J. Acoust. Soc. Am. 53, 1161-1166 (1973)]. The methods discussed in this paper can be used for a sparse unequally spaced array which is detecting a dispersive signal.
On errors in some papers on array processing
Hinich, Melvin J. (Acoustical Society of America, 1979-02)
Some errors in the literature are noted concerning the calculation of the maximum-likelihood estimator.
Estimating bearing when the source is endfire to an array
Hinich, Melvin J. (Acoustical Society of America, 1979-03)
Consider the problem of estimating the direction of arrival of a plane wave using a linear array of length L with M sensors. Let 0 denote the direction with respect to the array axis. Assume that we know that 0 >0. The sign of 0 is ambiguous, given data from a linear array. The approximations to the rms errors of the maximum likelihood 1-a and the least-squares 4 estimators of 0 are proportional to I sin0 1 'l. The Cramer-Rao bound also has this property. 5 This seems to imply that these estimators have infinite variances as 0-0. This is not the case, as I will now show.
Passive range estimation using subarray parallax
Hinich, Melvin J. (Acoustical Society of America, 1979-05)
Consider a large aperture linear array which is detecting coherent radiation from a source. Suppose that the array is processed as a string of subarrays consisting of adjacent sensors. Assume that the signal is a plane wave whose coherence distance is of the order of the subarray lengths. There is a systematic difference among the subarray bearing estimates due to parallax. A statistical method for using the parallax effect to estimate range is presented. Approximate expressions for the variance and bias of the estimator are derived under the assumption that the gain of each subarray is large. These theoretical results are compared with values obtained using artificial data for several parameter values.
Maximum likelihood estimation of the position of a radiating source in a waveguide
Hinich, Melvin J. (Acoustical Society of America, 1979-09)
An array of sensors is receiving radiation from a source of interest. The source and the array are in a one-or two-dimensional waveguide. The maximum-likelihood estimators of the coordinates of the source are analysed under the assumptions that the noise field is Gaussian. The Cramer-Rao lower bound is of the order of the number of modes which define the source excitation function. The results show that the accuracy of the maximum likelihood estimator of source depth using a vertical array in a infinite horizontal waveguide (such as the ocean) is limited by the number of modes detected by the array, regardless of the array size.
Beamforming when the sound velocity is not precisely known
Hinich, Melvin J. (Acoustical Society of America, 1980-08)
Beamforming is an integral part of most signal processingsystems in active or passive sonars. The delays used to generate a beam are functions of the sound velocity, which depends on temperature, salinity, and pressure. There is a loss in array gain if the delays are incorrectly set. This will occur when the sound velocity in the water surrounding the hydrophones is different from the velocity that was used to set the delays. This paper makes two points: (1) fixed delay line sonars suffer a loss in gain when the true sound speed in the water is different from the velocity that is used to set the delays, and (2) there are signal processing techniques for two- or three-dimensional arrays that yield source bearings that are independent of the true sound velocity. These techniques require variable time delays, which can be realized using digital processing.
Frequency-wave number array processing
Hinich, Melvin J. (Acoustical Society of America, 1981-03)
Most array signal processing systems use delay-and-sum beamforming to estimate source bearings. This paper demonstrates the close relationship between beamforming and frequency-wavenumber spectrum analysis. The latter approach has computational advantages over beamforming when the noise is spatially correlated. The wavenumber approach is used to derive the array response of a general linear or planar array to plane wave signals. The statistical properties of the maximum-likelihood estimators of source bearing and amplitude are presented for an array with many elements. Optimal array design is also discussed.
Statistical approach to passive target tracking
Hinich, Melvin J.; Bloom, Michael C. (Acoustical Society of America, 1981-03)
The paper presents a method for passively tracking a moving target using a sequence of bearings from a surveillance platform. The key assumption for the method is that the target is moving at a constant speed on a fixed heading during the data acquisition period. This is the same assumption that is made for Ekelund ranging. Parameter estimates are computed after bearings are taken as the tracking platforms maneuvers. No specific maneuver by the tracking platform is required. The estimators presented in this paper are approximately maximum likelihood when the target is distant from the platform.
Application of stochastic choice modeling to policy analysis of public-goods - a case-study of air-quality improvements
Loehman, E.; De, V. H. (MIT Press, 1982)
Estimating signal and noise using a random array
Hinich, Melvin J. (Acoustical Society of America, 1982-01)
This paper presents approximations for the rms error of the maximum likelihood estimator of the direction of a plane wave incident on a random array. The sensor locations are assumed to be realizations of independent, identically distributed random vectors. The second part of the paper presents an asymptotically unbiased estimator of the noise wavenumber spectrum from random array data.
Liquidity as a Latent Variable - an Application of the Mimic Model
Spanos, Aris (Blackwell, 1984-01-01)
Estimating the consumption and investment demands for housing and their effect on housing tenure status
Ioannides, Y. M.; Rosenthal, S. S. (MIT Press, 1994-02)
Theoretical work suggests that families live in owner-occupied housing if their investment demand for housing exceeds their consumption demand for housing. Using household data from the 1983 Survey of Consumer Finances, we test this theory by estimating an ordered probit model of whether families rent without owning property, rent while owning property other than their home, own their home without owning other properties, or own their home in addition to other properties. For owner-occupiers who own additional property, both the investment and consumption demands are directly observed enabling us to separately identify these functions. Results suggest that investment demand is more sensitive to wealth and income than is consumption demand, but that consumption demand is more sensitive to demographic variables and proximity to urban suburbs. In addition, test results indicate that the principal residence of most owner-occupiers is determined by their consumption demand for housing, not their investment demand. Hence, previous empirical housing demand studies likely to have identified the consumption demand for housing. Test results also suggest that, although the divergence between investment and consumption demand for housing is an important determinant of housing subtenure status, other factors also influence housing tenure decisions.
Non-nested Model Selection/Validation: Making Credible Postsample Inference Feasible
Ashley, Richard A. (Virginia Tech, 1995-04)
Effective, credible inference with respect to the postsample forecasting performance of time series models is widely held to be infeasible. Consequently, the model selection and Granger-causality literatures have focussed almost exclusively on in-sample tests, which can easily be biased by typical specification-search activity. Indeed, the postsample error series generated by competing models are typically cross-correlated, serially correlated, and not even clearly gaussian; thus, postsample inference procedures are necessarily only asymptotically valid. As a result, a postsample period large enough to yield credible inferences is perceived to be too costly in terms of sample observations foregone. This paper describes a new, re-sampling based, approach to postsample inference which, by explicitly quantifying the inferential uncertainty caused by the limited length of the postsample period, makes it feasible to obtain credible postsample inferences using postsample periods of reasonable length. For a given target level of inferential precision – e.g., significance at the 5% level – this new approach also provides explicit estimates of both how strong the postsample forecasting efficiency evidence in favor of one of two models must be (for a given length postsample period) and how long a postsample period is necessary, if the evidence is of given strength. These results indicate that postsample model validation periods substantially longer than the 5 to 20 periods typically reserved in past studies are necessary in order to credibly detect 20% - 30% MSE reductions. This approach also quantifies the inferential impact of different forecasting efficiency criterion choices – e.g., MSE vs. MAE vs. asymmetric criteria and the use of expected loss differentials (as in Diebold and Mariano(1994)) vs. ratios of expected losses. The value of this new approach to postsample inference is illustrated using postsample forecasting error data from Ashley, Granger, and Schmalensee(1980), in which evidence was presented for unidirectional Granger-causation from fluctuations in aggregate U.S. consumption expenditures to fluctuations in U.S. aggregate expenditures on advertising.
An Elementary Method for Detecting and Modeling Regression Parameter Variation Across Frequences With an Application to Testing the Permanent Income Hypothesis
Boon, Tan Hui; Ashley, Richard A. (Virginia Tech, 1997-03)
A simple technique for directly testing the parameters of a time series regression model for instability across frequencies is presented. The method can be easily implemented in the time domain, so parameter instability across frequency bands can be conveniently detected and modeled in conjunction with other econometric features of the problem at hand, such as simultaneity, cointegration, missing observations, cross-equation restrictions, etc. The usefulness of the new technique is illustrated with an application to a cointegrated consumption-income regression model, yielding a straightforward test of the permanent income hypothesis.
Property tax capitalization in a model with tax-deferred assets, standard deductions, and the taxation of nominal interest
de Bartolome, C. A. M.; Rosenthal, S. S. (MIT Press, 1999-02)
Previous property tax capitalization studies assume that families itemize, that they save in taxable assets, and that real interest income is taxed. However, many families do not itemize, many families invest in tax-deferred assets, and nominal interest income is taxed. As a consequence, prior studies likely misspecify the property tax capitalization equation for roughly ninety percent of their samples. Taking federal tax provisions into account increases the precision of our estimated capitalization rate. In addition, our results suggest that biases in prior studies likely contribute to the variety of capitalization estimates in the literature.
Residential buildings and the cost of construction: new evidence on the efficiency of the housing market
Rosenthal, S. S. (MIT Press, 1999-05)
Present value studies of asset market efficiency are controversial because they compare asset prices to unobserved discounted streams of future rents. As an alternative, if housing markets are efficient, then the price of residential capital or buildings should satisfy the following two conditions: (i) deviations between new building prices and construction costs should disappear faster than construction lags and have no effect on construction, and (ii) temporary building price shocks should dissipate at a similar rate for different vintage buildings. Results from an error-correction model support both hypotheses for single-family housing in Vancouver, British Columbia. This implies that the implicit market for residential buildings is efficient and that any inefficiencies in the housing market must lie in the market for land itself.

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