Magnetic Gimbal Proof-of-Concept Hardware performance results

The Magnetic Gimbal Proof-of-Concept Hardware activities, accomplishments, and test results are discussed. The Magnetic Gimbal Fabrication and Test (MGFT) program addressed the feasibility of using a magnetic gimbal to isolate an Electro-Optical (EO) sensor from the severe angular vibrations induced during the firing of divert and attitude control system (ACS) thrusters during space flight. The MGFT effort was performed in parallel with the fabrication and testing of a mechanically gimballed, flex pivot based isolation system by the Hughes Aircraft Missile Systems Group. Both servo systems supported identical EO sensor assembly mockups to facilitate direct comparison of performance. The results obtained from the MGFT effort indicate that the magnetic gimbal exhibits the ability to provide significant performance advantages over alternative mechanically gimballed techniques

Disentangling Access and View Amenities in Access-restricted Coastal Residential Communities

In small coastal communities with uniform flood risk, amenity value is comprised of two components – view and access. Having controlled for view, it is assumed that any residual amenity value represents the benefit derived from households from accessing the beach for leisure or recreational purposes. However, as properties closer to the beach typically have improved viewsheds, the two amenities are highly correlated, and disentangling view and access is problematical. We posit that for many coastal communities, access is restricted to designated public access points, precluding local residents from accessing the beach area directly from their property. To appropriately account for restricted access, we incorporate a network distance access measure into a spatial autoregressive hedonic model to capture ease of beach access for local residents. Our findings suggest that, as network distance varies independently from property viewshed, collinearity effects are mitigated, and access and view can be disentangled. Key Words:

Disentangling Access and View Amenities in Access-Restricted Coastal Residential Communities

In coastal communities with uniform flood risk, amenity value is comprised of two components – view and access. Having controlled for view, it is assumed that any residual amenity value represents the benefit derived from accessing the beach for leisure/recreational purposes. However, as properties closer to the beach typically have improved viewsheds, the two amenities are highly correlated, and disentangling view and access is problematical. A spatial autoregressive hedonic model captures ease of beach access via a network distance parameter that varies independently from property viewshed, collinearity effects are mitigated, and access and view can be disentangled.beach access, property viewshed, spatial hedonic model, willingness to pay, Environmental Economics and Policy, Land Economics/Use, Q51, R12, R21, R23,

Estimating a Payment Vehicle for Financing Nourishment of Residential Beaches using a Spatial-lag Hedonic Property Price Model

Beach nourishment projects are common methods for coastal states to protect beaches and property from the natural erosive process. However, while the beneficiaries of beach nourishment tend to be local property owners and recreators, projects are typically funded at the state level. Based on the benefit principle, as local residents receive more of the erosion protection benefits of the nourishment projects, we estimate a value capture tax, designed to levy the financing burden in a manner that approximates the distribution of benefits. The benefits of nourishment projects to coastal property owners are estimated using the results from a spatial-lag hedonic model that controls for viewshed effects. Key Words:

Gulf Views: Toward a Better Understanding of Viewshed Scope in Hedonic Property Models

This study examines the influence of Gulf of Mexico views on residential home sales prices in Pinellas County, Florida. We utilize Light Detection and Ranging (lidar) data to construct four continuous measures of Gulf of Mexico views – the total view, the maximum view segment, the mean view segment, and proximity to view content. Our results illustrate that residential property owners have a higher marginal willingness-to-pay for larger total views and larger continuous view segments. Results also indicate that the proximity of homes to the view content influences view valuations. Key Words:

Importance Sampling: Intrinsic Dimension and Computational Cost

The basic idea of importance sampling is to use independent samples from a proposal measure in order to approximate expectations with respect to a target measure. It is key to understand how many samples are required in order to guarantee accurate approximations. Intuitively, some notion of distance between the target and the proposal should determine the computational cost of the method. A major challenge is to quantify this distance in terms of parameters or statistics that are pertinent for the practitioner. The subject has attracted substantial interest from within a variety of communities. The objective of this paper is to overview and unify the resulting literature by creating an overarching framework. A general theory is presented, with a focus on the use of importance sampling in Bayesian inverse problems and filtering.Comment: Statistical Scienc

Water Quality and Residential Property Values: A Natural Experiment Approach

We use hedonic techniques to measure the impact of improved water quality on inland real estate values. By considering a unique natural experiment setting where consistent and recognizable variation in water quality across two rivers within a small geographic area is well known to market participants, we avoid the major problems inherent in hedonic water quality studies. Controlling for spatial autocorrelation, results show that land and property values increase more substantially with proximity to the non-contaminated river as opposed to the mercurycontaminated river that carries a fish consumption advisory. Results suggest that the value of improving water quality to a level that will remove the advisory is between $7.3 and$12 million. Key Words:

MCMC methods for functions modifying old algorithms to make\ud them faster

Many problems arising in applications result in the need\ud to probe a probability distribution for functions. Examples include Bayesian nonparametric statistics and conditioned diffusion processes. Standard MCMC algorithms typically become arbitrarily slow under the mesh refinement dictated by nonparametric description of the unknown function. We describe an approach to modifying a whole range of MCMC methods which ensures that their speed of convergence is robust under mesh refinement. In the applications of interest the data is often sparse and the prior specification is an essential part of the overall modeling strategy. The algorithmic approach that we describe is applicable whenever the desired probability measure has density with respect to a Gaussian process or Gaussian random field prior, and to some useful non-Gaussian priors constructed through random truncation. Applications are shown in density estimation, data assimilation in fluid mechanics, subsurface geophysics and image registration. The key design principle is to formulate the MCMC method for functions. This leads to algorithms which can be implemented via minor modification of existing algorithms, yet which show enormous speed-up on a wide range of applied problems

Charles, Arthur H. oral history interview

Arthur H. Charles was born in Portland, Maine on July 1, 1911 to Florence and John Charles. He was educated in the Portland public schools, graduating from Portland High School. He took a post-graduate year at Hebron Academy before enrolling at Boston University. He left Boston University after his second year because of health problems and completed his college education through classes at Portland College, now University of Southern Maine. His father was a grocer, and President of the Maine Grocers Association. He worked for his father as executive secretary of the association, eventually making it his career. In the 1930s he began lobbying in Augusta for the Grocers Association. He worked with Ed Muskie in the Office of Price Stabilization during World War II, because he had a relationship with the grocers of Maine. He served in the Maine House in the mid-1950s, and served one term in the Maine Senate in the late 1950s. He retired from the grocery industry after more than fifty years. His wife, Helen Charles, worked with him in the grocery business