Plan stability: replanning versus plan repair

The ultimate objective in planning is to construct plans for execution. However, when a plan is executed in a real environment it can encounter differences between the expected and actual context of execution. These differences can manifest as divergences between the expected and observed states of the world, or as a change in the goals to be achieved by the plan. In both cases, the old plan must be replaced with a new one. In replacing the plan an important consideration is plan stability. We compare two alternative strategies for achieving the {em stable} repair of a plan: one is simply to replan from scratch and the other is to adapt the existing plan to the new context. We present arguments to support the claim that plan stability is a valuable property. We then propose an implementation, based on LPG, of a plan repair strategy that adapts a plan to its new context. We demonstrate empirically that our plan repair strategy achieves more stability than replanning and can produce repaired plans more efficiently than replanning

Archaeological Studies for the San Antonio Channel Improvement Project, including Investigations at Guenther\u27s Upper Mill (41BX342)

Under Contract No. DACW63-81-C-0022 to the Department of the Army, Corps of Engineers, Fort Worth District, the Center for Archaeological Research, The University of Texas at San Antonio, in the spring of 1981, conducted historic research and survey in the areas to be affected by the San Antonio Channel Improvement Project. In the summer of 1981, extensive archaeological testing and excavation were done to determine the extent of the structural remains on the sites of Guenther\u27s Upper Mill and the Stribling House. In the spring and summer of 1982, the Center documented the removal and replacement of the mill\u27s west wall. As a result of the investigations, it can now be affirmed that most of the foundation of the east section of the mill is still present beneath the ground. The main foundation walls are made of cut limestone and measure two feet in thickness, except for the west wall which is three feet thick. Of the other buildings at various times related to the mill, only portions of a late (ca. 1910) stone and cement foundation for the Reigler Creamery still remain in the ground. The survey revealed no other cultural resources to be affected by the project

Is the Health Care System Working for Adolescents? Perspectives From Providers in Boston, Denver, Houston, and San Francisco

Assesses healthcare system services for adolescents in four urban areas. Includes provider perspectives on how health insurance, managed care, and other factors facilitate or impede access. Discusses innovative programs, and offers recommendations

Bayesian Nonparametric Inference of Switching Linear Dynamical Systems

Many complex dynamical phenomena can be effectively modeled by a system that switches among a set of conditionally linear dynamical modes. We consider two such models: the switching linear dynamical system (SLDS) and the switching vector autoregressive (VAR) process. Our Bayesian nonparametric approach utilizes a hierarchical Dirichlet process prior to learn an unknown number of persistent, smooth dynamical modes. We additionally employ automatic relevance determination to infer a sparse set of dynamic dependencies allowing us to learn SLDS with varying state dimension or switching VAR processes with varying autoregressive order. We develop a sampling algorithm that combines a truncated approximation to the Dirichlet process with efficient joint sampling of the mode and state sequences. The utility and flexibility of our model are demonstrated on synthetic data, sequences of dancing honey bees, the IBOVESPA stock index, and a maneuvering target tracking application.Comment: 50 pages, 7 figure

A sticky HDP-HMM with application to speaker diarization

We consider the problem of speaker diarization, the problem of segmenting an audio recording of a meeting into temporal segments corresponding to individual speakers. The problem is rendered particularly difficult by the fact that we are not allowed to assume knowledge of the number of people participating in the meeting. To address this problem, we take a Bayesian nonparametric approach to speaker diarization that builds on the hierarchical Dirichlet process hidden Markov model (HDP-HMM) of Teh et al. [J. Amer. Statist. Assoc. 101 (2006) 1566--1581]. Although the basic HDP-HMM tends to over-segment the audio data---creating redundant states and rapidly switching among them---we describe an augmented HDP-HMM that provides effective control over the switching rate. We also show that this augmentation makes it possible to treat emission distributions nonparametrically. To scale the resulting architecture to realistic diarization problems, we develop a sampling algorithm that employs a truncated approximation of the Dirichlet process to jointly resample the full state sequence, greatly improving mixing rates. Working with a benchmark NIST data set, we show that our Bayesian nonparametric architecture yields state-of-the-art speaker diarization results.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS395 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

A Happy Marriage of Inconvenience: The Power of Adrienne de La Fayette over her Destiny in Eighteenth-Century France

Extensive analysis and interpretation have occurred concerning the Marquis de Lafayette and his contributions to the American War for Independence and the Revolutionary French era. However, the discourse on his wife, Adrienne de Noailles, the Marquise de La Fayette, has been confined to a chapter within her husband\u27s larger narrative. Examining her agency over her circumstances, Adrienne proves to be more than an idealistic angel suffering from a tumultuous time period