Abstracts

Journal of the American Oil Chemists' Society -     

Translation and Run-Time Validation of Optimized Code

The paper presents approaches to the validation of optimizing compilers. The emphasis is on aggressive and architecture-targeted optimizations which try to obtain the highest performance from modern architectures, in particular EPIC-like micro-processors. Rather than verify the compiler, the approach of translation validation performs a validation check after every run of the compiler, producing a formal proof that the produced target code is a correct implementation of the source code.First we survey the standard approach to validation of optimizations which preserve the loop structure of the code (though they may move code in and out of loops and radically modify individual statements), present a simulation-based general technique for validating such optimizations, and describe a tool, VOC-64, which implements these technique. For more aggressive optimizations which, typically, alter the loop structure of the code, such as loop distribution and fusion, loop tiling, and loop interchanges, we present a set of permutation rules which establish that the transformed code satisfies all the implied data dependencies necessary for the validity of the considered transformation. We describe the necessary extensions to the VOC-64 in order to validate these structure-modifying optimizations.Finally, the paper discusses preliminary work on run-time validation of speculative loop optimizations, that involves using run-time tests to ensure the correctness of loop optimizations which neither the compiler nor compiler-validation techniques can guarantee the correctness of. Unlike compiler validation, run-time validation has not only the task of determining when an optimization has generated incorrect code, but also has the task of recovering from the optimization without aborting the program or producing an incorrect result. This technique has been applied to several loop optimizations, including loop interchange, loop tiling, and software pipelining and appears to be quite promising.     

Employment opportunities for geropsychologists.

Surveyed 224 hospitals, community mental health centers, nursing homes, graduate departments of psychology, and hospices in California, Michigan, New York, and Texas as to their present and future levels of providing services to the aging and their interest in hiring geropsychologists. The most prevalent geropsychological activities were therapy, assessment, and community consultation. Although only 10% of respondents were interested in hiring geropsychologists at present, 43% reported interest in hiring in the future. The greatest interest in hiring was expressed by community mental health centers and hospitals. Regionally, New York expressed the greatest interest. Consistent with the recognized discrepancy between the extensive mental health needs of the elderly and the availability of appropriate professional care, the results document that the employment market for geropsychologists is considerably underdeveloped. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Liveness with invisible ranking

The method of invisible invariants was developed originally in order to verify safety properties of parameterized systems in a fully automatic manner. The method is based on (1) a project&generalize heuristic to generate auxiliary constructs for parameterized systems and (2) a small-model theorem, implying that it is sufficient to check the validity of logical assertions of a certain syntactic form on small instantiations of a parameterized system. The approach can be generalized to any deductive proof rule that (1) requires auxiliary constructs that can be generated by project&generalize, and (2) the premises resulting when using the constructs are of the form covered by the small-model theorem. The method of invisible ranking, presented here, generalizes the approach to liveness properties of parameterized systems. Starting with a proof rule and cases where the method can be applied almost “as is,” the paper progresses to develop deductive proof rules for liveness and extend the small-model theorem to cover many intricate families of parameterized systems.     

The Synergy™ HT - A Unique Multi-Detection Microplate Reader for HTS and Drug Discovery

Pharmaceutical and biotechnology research requires instrumentation to be both functional and versatile. In the HTS and Drug Discovery environments, microplate based assays are developed to make determinations on large numbers of samples. Regardless of the assay protocol, the end result is the measurement by some sort of detection device. Towards that end, Bio-Tek has developed the Synergy™ HT Multi-Detection microplate reader. Microplate Reader. Synergy HT utilizes two independent sets of optics to provide uncompromised performance. For absorbance measurements, there is a xenon-flash lamp with a monochromator for wavelength selection and photodiode detection. This allows the selection of any wavelength for endpoint or kinetic measures from 200 nm to 999 nm in 1 nm increments, as well as spectral scans. Traditional visible wavelength fluorescence measurements are made using a tungsten-halogen lamp with interference filters (excitation and emission) for wavelength selection and photomultiplier (PMT) detection. Glow luminescence measurements are also easily accomplished in Synergy HT. If time-resolved or UV excitation fluorescence measurements are required, Synergy HT automatically integrates the xenon-flashmonochromator excitation with the interference emission filter and PMT detection. Typical applications include antibody-antigen binding, receptor-liquid binding, ELISA, nucleic acid quantitation using fluorescent dyes or direct UV analysis. Synergy HT is capable of reading any plate format up to 384-well plates and provides temperature control up to 50° C and shaking as standard features. It is compact (16″ W × 15″ D × 10″ H) and robotics-compatible through the OLE functionality of the KC4™ data reduction software that is bundled with the instrument. An upgrade to CFR 21 Part 11 compliant software is also available.     

Determination of absorption coefficients for chlorophyll a,phycocyanin, mineral matter and CDOM from three central Indiana reservoirs

Absorption coefficients are used in semi-empirical and bio-optical models to estimate various optically active constituents in water. This study determines the mass-specific absorption coefficients of chlorophyll a (a*_chl), phycocyanin (a*_pc), minerals (a*_m), and chromophoric dissolved organic matter (CDOM; a*_CDOM) and the absorption coefficient for CDOM (a_CDOM) for three central Indiana reservoirs. Absorption spectra were collected using a Shimadzu spectrophotometer equipped with a Spectralon coated integrating sphere. Quantitative measurements from either fluorometric (chlorophyll a, phycocyanin, CDOM) or weight-based (mineral) measurements were used to determine the mass-specific absorption coefficients tested in this study and an exponential function was used to estimate a_CDOM. While a*_chl showed minimum variability between reservoirs, a*_pc, a*_m, a*_CDOM, and a_CDOM showed statistically significant differences between reservoirs; however, for a*_m, there was greater variation within each reservoir. Variability in a*_CDOM and a_CDOM between reservoirs was likely due to different inflows. All absorption coefficients fell within previously published ranges for each constituent examined, with the exception of a*_pc. Differences in a*_pc were likely due to different techniques used in extracting and estimating phycocyanin.