Measurement scheduling for recursive team estimation

We consider a decentralized LQG measurement scheduling problem in which every measurement is costly, no communication between observers is permitted, and the observers' estimation errors are coupled quadratically. This setup, motivated by considerations from organization theory, models measurement scheduling problems in which cost, bandwidth, or security constraints necessitate that estimates be decentralized, although their errors are coupled. We show that, unlike the centralized case, in the decentralized case the problem of optimizing the time integral of the measurement cost and the quadratic estimation error is fundamentally stochastic, and we characterize the ε-optimal open-loop schedules as chattering solutions of a deterministic Lagrange optimal control problem. Using a numerical example, we describe also how this deterministic optimal control problem can be solved by nonlinear programming.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45246/1/10957_2005_Article_BF02275352.pd

A Functional Screen Provides Evidence for a Conserved, Regulatory, Juxtamembrane Phosphorylation Site in Guanylyl Cyclase A and B

Kinase homology domain (KHD) phosphorylation is required for activation of guanylyl cyclase (GC)-A and -B. Phosphopeptide mapping identified multiple phosphorylation sites in GC-A and GC-B, but these approaches have difficulty identifying sites in poorly detected peptides. Here, a functional screen was conducted to identify novel sites. Conserved serines or threonines in the KHDs of phosphorylated receptor GCs were mutated to alanine and tested for reduced hormone to detergent activity ratios. Mutation of Ser-489 in GC-B to alanine but not glutamate reduced the activity ratio to 60% of wild type (WT) levels. Similar results were observed with Ser-473, the homologous site in GC-A. Receptors containing glutamates for previously identified phosphorylation sites (GC-A-6E and GC-B-6E) were activated to ∼20% of WT levels but the additional glutamate substitution for S473 or S489 increased activity to near WT levels. Substrate-velocity assays indicated that GC-B-WT-S489E and GC-B-6E-S489E had lower Km values and that WT-GC-B-S489A, GC-B-6E and GC-B-6E-S489A had higher Km values than WT-GC-B. Homologous desensitization was enhanced when GC-A contained the S473E substitution, and GC-B-6E-S489E was resistant to inhibition by a calcium elevating treatment or protein kinase C activation – processes that dephosphorylate GC-B. Mass spectrometric detection of a synthetic phospho-Ser-473 containing peptide was 200–1300-fold less sensitive than other phosphorylated peptides and neither mass spectrometric nor 32PO4 co-migration studies detected phospho-Ser-473 or phospho-Ser-489 in cells. We conclude that Ser-473 and Ser-489 are Km-regulating phosphorylation sites that are difficult to detect using current methods

Trace Recovery: A Distributed Computing Application for Perturbation Tracking

Execution monitoring plays a central role in most software development tools for parallel and distributed computer systems. However, such monitoring may induce delays that corrupt event timing. In this paper we introduce a perturbation analysis-like algorithm that, given a safe timed Petri net model of the monitored software, can recover the uncorrupted event timings, i.e., those that would have been observed had the delays not been present. Monitoring conditions sufficient to ensure correct operation of the algorithm, and examples illustrating the algorithm's applicability to message-passing systems are also presented. This work is part of a larger effort aimed at identifying cost-effective software alternatives to custom hardware monitoring

Using Perturbation Tracking to Compensate for Instrusion in Message-Passing Systems

Execution monitoring plays a central role in most software development tools for parallel and distributed computer systems. However, such monitoring may induce delays that corrupt event timing. If this corruption can be quantified it may be possible to determine the intrusion-free behavior. In this paper we describe an algorithm that, given a safe timed Petri net model of the monitored software, can determine the uncorrupted timestamp values, i.e., those that would have been observed had the delays not been present. Monitoring conditions sufficient to ensure correct operation of the algorithm, and examples illustrating the algorithm 's applicability to message-passing systems are also presented. This work is part of a larger effort aimed at identifying cost effective software alternatives to custom hardware monitoring. 1. Introduction This paper describes a trace compensation algorithm developed as part of a larger study aimed at using software instrumentation, minimal generic hardwa..

Triaging HPV-Positive Cervical Samples with p16 and Ki-67 Dual Stained Cytology within an Organized Screening Program—A Prospective Observational Study from Western Norway

The implementation of high-risk human papillomavirus testing (hrHPV testing) as a screening method in substitute for cytology has evoked the need for more sensitive and less objective tests for the triage of HPV-positive women. In a cohort of 1763 HPV-positive women, the potential of immunocytochemical p16 and Ki-67 dual staining as compared to cytology, alone or in combination with HPV partial genotyping, was tested for triage of women attending a cervical cancer screening program. Performance was measured using sensitivity, specificity, and positive and negative predictive values. Comparisons were assessed using logistic regression models and the McNemar test. Dual staining was evaluated in a prospectively collected study cohort of 1763 HPV-screened women. For triage of CIN2+ and CIN3+, NPV and sensitivity, 91.8% and 94.2% versus 87.9% and 89.7%, respectively, were significantly higher using dual staining together with HPV 16/18 positive, as compared to cytology (p < 0.001). The specificities, however, were lower for dual staining as compared to cytology. Conclusions: Dual staining is safer for decision-making regarding HPV-positive women’s need for follow-up with colposcopy and biopsy, as compared to cytology