Identification Of Possible Errors Research Articles

Validation of IMERG Oceanic Precipitation over Kwajalein

The integrated Multi-satellitE Retrievals for GPM (IMERG) Version V05B and V06B precipitation products from the Global Precipitation Measurement (GPM) mission are validated against ground-based observations from the Kwajalein Polarimetric S-band Weather Radar (KPOL) deployed at Kwajalein Atoll in the central Pacific Ocean. Such a validation is particularly important as comprehensive surface measurements over the oceans are practically infeasible, which hampers the identification of possible errors, and improvement of future versions of IMERG and other satellite-based retrieval algorithms. The V05B and V06B IMERG products are validated at their native 0.1°, 30 min resolution from 2014 to 2018 based on both volumetric and categorical metrics. This validation study indicates that precipitation rates from both IMERG V05B and V06B are underestimated with respect to radar surface estimates, but the underestimation is much reduced from V05B to V06B. IMERG V06B outperforms V05B with reduced systematic bias and improved precipitation detectability. The IMERG performance is further traced back to its individual sensors and morphing-based algorithms. The overall underestimation in V05B is mainly driven by the negative relative biases from morphing-based algorithms which are largely corrected in V06B. Imagers perform generally better than sounders because of the usage of low-frequency channels in imagers which can better detect emission signals by the hydrometeors. Among imagers, the GPM Microwave Imager (GMI) and Advanced Microwave Scanning Radiometer Version 2 (AMSR2) are the best, followed by Special Sensor Microwave Imager/Sounder (SSMIS). Among sounders, the Microwave Humidity Sounder (MHS) is the best, followed by Advanced Technology Microwave Sounder (ATMS) and the Sounder for Atmospheric Profiling of Humidity in the Intertropics by Radiometry (SAPHIR) for V06B. Among all categories, morph-only and IR + morph only perform better than SAPHIR. SAPHIR shows the worst performance among all categories, likely due to its limited channel selection. It is envisaged that these results will improve our understanding of IMERG performance over oceans and aid in the improvement of future versions of IMERG.

Modeling of Programs and its Verification for Programmable Logic Controllers

Programmable logic controller is still the main device used for control of productive systems, which can be approached as discrete event dynamic systems. For programming these controllers, five languages were standardized by IEC 61131, and the LD (ladder diagram) language is distinguished among the others, i.e., it has been widely applied in productive systems, even with studies that confirm the restrictions and problems regarding the use of this language, such as the difficulties for errors identification in developed control programs. Therefore, this work presents a proposal for the modeling of extended finite state machines from control programs written in LD. These models are verified through a computational tool, aiming the identification of possible errors in the control program.

Error‐sensitive historical GIS: Identifying areal interpolation errors in time‐series data

Historical GIS has the potential to re‐invigorate our use of statistics from historical censuses and related sources. In particular, areal interpolation can be used to create long‐run time‐series of spatially detailed data that will enable us to enhance significantly our understanding of geographical change over periods of a century or more. The difficulty with areal interpolation, however, is that the data that it generates are estimates which will inevitably contain some error. This paper describes a technique that allows the automated identification of possible errors at the level of the individual data values.

Multivariate analysis in hydrology: the factor correspondence analysis method applied to annual rainfall data

Most research on hydrology in developed countries does not emphasize problems that are often encountered by hydrologists in developing countries, problems such as the scarcity and poor quality of data. In developing countries the available data base is often a major constraint and a limiting factor in any hydrological study. This paper analyses the consistency of a network of nonrecording raingauges based on the annual rainfall recorded by six representative stations in the Tacuarembô River basin in Uruguay. The identification of possible errors not revealed in the printed records was accomplished by application of the factor correspondence analysis method and verified with success by the classical double-mass analysis. This ability to identify suspicious data with very modest requirements for data management implies that the methodology based on factor correspondence analysis could find wide application.

Tandem mass spectrometry of very large molecules: serum albumin sequence information from multiply charged ions formed by electrospray ionization

Serum albumin proteins, Mr approximately 66 kDa, from 10 different species (bovine, human, rat, horse, sheep, goat, rabbit, dog, porcine, and guinea pig) have been studied by electrospray ionization mass spectrometry (ESI-MS) and tandem MS using a triple-quadrupole instrument. The effectiveness of collisional activation for the multiply charged albumin ions greatly exceeds that for singly charged ions, allowing an extension by a factor of at least 20 to the molecular mass range for obtaining sequence-specific product ions by tandem MS. Efficient dissociation is largely attributed to "preheating" in the interface Coulombic instability and the large number of collisions. Increasing the electric field in the intermediate pressure region, between the nozzle-skimmer elements of the atmospheric pressure/vacuum interface, allows fragmentation of the multiply protonated (to 96+) molecules produced by ESI. The most abundant dissociation product ions assigned have a low charge state (2+ to 5+) and are attributed to "bn" mode species from cleavage of the -CO-N- peptide backbone bonds. Particularly abundant dissociation products originate from regions near residues n = 20-25 from the NH2 terminus for parent ions of moderate charge (approximately 50+). Collisionally activated dissociation (CAD) mass spectra from porcine serum albumin, in contrast to the other albumins, also gave prominent singly charged "yn" fragments formed from cleavages near the COOH terminus. Tandem mass spectrometry (MS/MS) of the multiply charged molecular ions, and of fragment species produced by dissociation in the interface (i.e., effective MS/MS/MS), produced similar "bn" species and served to confirm spectral assignments. We also show that ESI mass spectra allow a qualitative assessment of protein microheterogeneity and, in some cases, resolution of major contributions. The physical and analytical implications of the results are discussed, including the identification of possible errors in previously published sequences.

Computer identification of brachial arterial pulse waves

A digital computer program is described for automatic identification of the clinically important points in the externally recorded brachial pulse wave. The logic of recognition is designed to locate these points in any type of brachial pulse wave. Intrinsic to the program is the identification of possible errors of recognition at each step. In 332 brachial pulse wave records comparisons between statistics calculated from the computer identified points with corresponding measurements calculated from points identified by an experienced physician showed correlation coefficients varying between .94 and .99 indicating good agreement.