A Focus Research Sampler -2004

Evaluation of a personal and microenvironmental aerosol speciation sampler (PMASS).

In this study, an all-aluminum sampler was reconfigured to a lighter weight by using plastic for structural components not contacted by aerosol. Because the sampler body was made of plastic, the aluminum size-selective cyclone inlet was redesigned into a separate, removable unit. The resulting personal and microenvironmental aerosol speciation sampler (PMASS*) is a small, compact sampler design...

Optimal scaling of the independence sampler: Theory and Practice

The independence sampler is one of the most commonly used MCMC algorithms usually as a component of a Metropolis-within-Gibbs algorithm. The common focus for the independence sampler is on the choice of proposal distribution to obtain an as high as possible acceptance rate. In this paper we have a somewhat different focus concentrating on the use of the independence sampler for updating augment...

Side by Side Comparison of the Aerotrap Total Fungal Sampler with Grease Slides, the Aerotrap Total Fungal Sampler with Glyceryl Triacetate Cleared Mixed Cellulose Ester Membrane Filter Slides and the Zefon Bio-Pump using the Zefon Air-O-Cell

From Fields to Trees

We present new MCMC algorithms for computing the posterior distributions and expectations of the unknown variables in undirected graphical models with regular structure. For demonstration purposes, we focus on Markov Random Fields (MRFs). By partitioning the MRFs into non-overlapping trees, it is possible to compute the posterior distribution of a particular tree exactly by conditioning on the ...

A Gibbs Sampler for Spatial Clustering with the Distance-dependent Chinese Restaurant Process

The distance-dependent Chinese Restaurant Process (dd-CRP) is a flexible class of distributions over partitions which was recently introduced by [1, 2]. In their description and experiments Blei and Frazier focus on the sequential setting such as clustering over time. Their Gibbs sampler, while general in nature, does not explicitly handle the case of non-sequential (also called spatial) cluste...