A hypothetical application of the Statistical Modeling and Estimation of Reliability Functions for Software (SMERFS) to Knowledge-Based Systems (KBSs)

Software reliability models are applied to conventional software to compute several important quantities. Two of these are the rate at which software fails and the number of software faults remaining in software. The software failure rate and the number of faults remaining in software are measures of software trustworthiness or reliability. Software reliability models, however, have never been applied to knowledge-based systems to determine these quantities. This paper reports a hypothetical application of the Statistical Modeling and Estimation of Reliability Functions for Software (SMERFS) to knowledge-based systems. SMERFS, developed by the Naval Surface Warfare Center (NSWC), contains a representative set of software reliability models “chosen for their performance in comparative studies and their ability to handle data collected from various testing environments.”     

Performance of optical ground wires during fault current tests

Optical ground wires (OPGW) must be able to fulfil the regular functions of a ground wire, such as lighting protection and fault current path, as well as provide secure communications by way of the optical fibers embedded inside. Fault current tests were performed on a loose-tube-design OPGW to evaluate the temperature and optical performance during and after fault current pulses or hits. Optical performance was found to be affected as early as the first rated fault current hit. Temperature gradient tests revealed much higher than expected optical core temperatures, with resultant buffer tube damage. A computer program for predicting the temperature gradient was developed and independently verified the measured temperatures. A redesign of the cable will be necessary to ensure adequate optical performance for rated fault current hits     

The economics of oil supply dynamics : Theory and practice

This paper develops a model of oil supply where firms, in attempting to keep extraction costs down, build up reserves not only by discovering and developing new reservoirs but also by increasing the recovery of previously discovered deposits. This approach is therefore consistent with the definition of reserves corresponding to the data used in most empirical analyses. The functions underlying the theoretical model are estimated econometrically using data for Alberta, Canada, and ‘optimal’ solutions are simulated and compared with the observed dynamics. This exercise suggests that reserves have perhaps been built up at a rate that is greater than the socially optimal rate.     

Static and dynamic cyclic oxidation of 12 nickel-, cobalt-, and iron-base high-temperature alloys

Twelve typical high-temperature nickel-, cobalt-, and iron-base alloys were tested by 1 hr cyclic exposures at 1038, 1093, and 1149°C and 0.05 hr exposures at 1093°C. The alloys were tested in both a dynamic burner rig at Mach 0.3 gas flow and in static air furnace for times up to 100 hr. The alloys were evaluated in terms of specific weight loss as a function of time, and X-ray diffraction analysis and metallographic examination of the posttest specimens. A method previously developed was used to estimate specific metal weight loss from the specific weight change of the sample. The alloys were then ranked on this basis. In general the burner-rig test was more severe than a comparable furnace test and resulted in an increased tendency for oxide spalling due to volatility of Cr in the protective scale and the more dratic cooling due to the air-blast quench of the samples. Increased cycle frequency also increased the tendency to spall for a given test exposure. The behavior of the alloys in both types of tests was related to their composition, particularly their Cr and Al contents and their tendency to form four types of scales: NiO or CoO, Cr₂O₃-chromite spinel, -Al₂O₃-aluminate spinel, or ThO₂-blocked Cr₂O₃. The alloys with the best overall behavior formed -Al₂O₃-aluminate spinels.     

Independently derived IgG anti-DNA autoantibodies from two lupus-prone mouse strains express a VH gene that is not present in most murine strains

The origin and structure of two clonally unrelated IgG anti-DNA autoantibodies from lupus-prone MRL/Ipr mice were examined. One of these antibodies, H241, binds dsDNA and glomeruli and deposits in the kidneys of normal mice, whereas the other, H102, binds only ssDNA and does not deposit in kidneys. The VH genes of these two antibodies were almost identical to each other and were frequently expressed in anti-DNA antibodies derived from lupus-prone mice. Six other clonally unrelated anti-DNA antibodies from the literature or from data banks expressed nearly identical VH genes (< or = 4 nucleotide differences) and eight others had nearly identical protein sequences (< or = 3 amino acid differences). Analysis of the germ line with oligonucleotide probes from the CDR regions suggests that all 10 autoantibodies are derived from a single member of the J558 gene family, which is present only in mice with the j haplotype for the J558 gene family. The amount of somatic mutation in these VH genes appears to be low, suggesting that some V, N, and D gene combinations can generate high affinity IgG anti-DNA auto-antibodies with little or no somatic mutation. Unusual reading frames, D-D fusions, and inversions were common in the IgG antibodies and may have been co-selected. Although the N and D regions of one IgM and all five IgG autoantibodies contained Arg residues, the presence of Arg residues was not correlated with binding to dsDNA or with pathogenicity. These results suggest that differences in the Ag-binding properties and the pathogenicity of these antibodies are determined by the CDR3 region and the L chain.     

COMBINED ACIDULATION AND GIBBERELLIC ACID TREATMENT IN THE ACCELERATED MALTING OF ABRADED BARLEY*

Pilot-scale malting trials show that when slight acidulation of the steeping water is combined with a high level of gibberellic acid, abraded barley produces a full extract in only 72 h. Acidulation also inhibits growth of the rootlets, curbing malting loss, in addition to encouraging higher levels of total soluble nitrogen.     

THE RELATIVE CONTRIBUTIONS TO WORT NITROGEN OF NITROGENOUS SUBSTANCES SOLUBILIZED DURING MALTING AND MASHING

Treatment of ground malt with boiling ethanol fails to inactivate proteolytic and amylolytic enzymes completely, whereas boiling aqueous ethanol (80% v/v) is effective. Proteolytic activity during infusion mashing of all-malt grists is responsible for the production of nearly half of the nitrogenous compounds and amino nitrogen of wort. The percentage of the nitrogen solubilized during malting and mashing which consists of amino nitrogen is almost identical in the two processes.     

Antigonococcal activity of 11 drugs used for therapy or prophylaxis of malaria

Antibacterial agents are often used in malarial endemic areas for antimalarial prophylaxis (such as doxycycline and clindamycin). Gonococcal infections may coexist in the same geographic area, thus becoming suppressed by compounds directed toward malarial parasites. We tested 11 drugs with activity for Plasmodium species against 105 Neisseria gonorrhoeae strains. Traditional or investigational antimalarials such as arteflene (Ro 42-1611), chloroquine, primaquine, pyrimethamine, quinacrine, and quinine were observed to be inactive. Fansidar (sulfadoxine-pyrimethamine) and mefloquine possess marginal action in a minority of gonococcus strains (< 10%). Doxycycline [minimum inhibitory concentration inhibiting 90% of tested strains (MIC 90) 2 micrograms/ml] and azithromycin (MIC 90, 0.5 microgram/ml) among the antibacterials were very active, indicating a dual role as antimalarial and antigonococcal agents. Thus, the gonorrhea and sexually transmitted disease epidemiologic data from geographic regions where doxycycline or newer macrolides may be used for malarial prophylaxis or therapy could be significantly altered.