An implementation of Deflate in Coq

The widely-used compression format "Deflate" is defined in RFC 1951 and is based on prefix-free codings and backreferences. There are unclear points about the way these codings are specified, and several sources for confusion in the standard. We tried to fix this problem by giving a rigorous mathematical specification, which we formalized in Coq. We produced a verified implementation in Coq which achieves competitive performance on inputs of several megabytes. In this paper we present the several parts of our implementation: a fully verified implementation of canonical prefix-free codings, which can be used in other compression formats as well, and an elegant formalism for specifying sophisticated formats, which we used to implement both a compression and decompression algorithm in Coq which we formally prove inverse to each other -- the first time this has been achieved to our knowledge. The compatibility to other Deflate implementations can be shown empirically. We furthermore discuss some of the difficulties, specifically regarding memory and runtime requirements, and our approaches to overcome them

Energy Expenditure of Structural Firefighters During a Typical Work Shift

This study examined the energy expenditure and heart rate of structural firefighters. Subjects included nine (N=9) full-time firefighters from Ithaca, NY, ranging in age from 21-48 years. All subjects completed four test days. Test day 1 included measurement of VO2max and anthropometric data. During test days 2-4, activity count to estimate energy expenditure (EE) and heart rate (HR) were measured simultaneously using an Actiheart Monitor. During each shift (test days 2-4), subjects were required to document all activity at 15 minute increments. Activities were subsequently classified as emergency response (ER), simulation training (ST) or other shift activities (SA), and were synchronized with the activity count and heart rate data from the Actiheart. A 3x2 repeated measures ANOVA compared heart rate and activity count between ER and SA during the three test days. Data during ST was captured on only one firefighter therefore ST data was not included in the statistical analysis due to small sample size. As expected, mean HR was significantly higher during ER compared to SA. Surprisingly, EE during SA was significantly higher than EE during ER. The large difference could be due to the variety and intensity of tasks completed during SA and the amount of time during those activities. Accurate exercise prescription is essential to meet the physiological demands of the profession. Physical demands affect job performance and ultimately public safety. Shift activities like truck checks and truck washing should be considered when prescribing exercise to this population

Use of a Granulocyte Immunofluorescence Assay Designed for Humans for Detection of Antineutrophil Cytoplasmic Antibodies in Dogs with Chronic Enteropathies

Perinuclear antineutrophil cytoplasmic antibodies (pANCA) previously have been shown to be serum markers in dogs with chronic enteropathies, with dogs that have food‐responsive disease (FRD) having higher frequencies of seropositivity than dogs with steroid‐responsive disease (SRD). The indirect immunofluorescence (IIF) assay used in previous publications is time‐consuming to perform, with low interobserver agreement. Forty‐four dogs with FRD, 20 dogs with SRD, 20 control dogs, and 38 soft‐coated wheaten terrier (SCWT) or SCWT‐cross dogs

Notes

Notes by Robert J. Affeldt, Andrew V. Giorgi, Mark Harry Berens, Robert C. Enburg, James J. Haranzo, F. Richard Kramer, George J. Murphy, Jr., James F. O\u27Rieley, and Edward J. VanTassel

Cost-benefit analysis for commissioning decisions in GEO600

Gravitational wave interferometers are complex instruments, requiring years of commissioning to achieve the required sensitivities for the detection of gravitational waves, of order 10^-21 in dimensionless detector strain, in the tens of Hz to several kHz frequency band. Investigations carried out by the GEO600 detector characterisation group have shown that detector characterisation techniques are useful when planning for commissioning work. At the time of writing, GEO600 is the only large scale laser interferometer currently in operation running with a high duty factor, 70%, limited chiefly by the time spent commissioning the detector. The number of observable gravitational wave sources scales as the product of the volume of space to which the detector is sensitive and the observation time, so the goal of commissioning is to improve the detector sensitivity with the least possible detector down time. We demonstrate a method for increasing the number of sources observable by such a detector, by assessing the severity of non-astrophysical noise contaminations to efficiently guide commissioning. This method will be particularly useful in the early stages and during the initial science runs of the aLIGO and adVirgo detectors, as they are brought up to design performance.Comment: 17 pages, 17 figures, 2 table