Empirical tests of multipliers for the prime-modulus random number generator Xi[subscript i]b 1s [if and only if] AXb1s mod 2p31s-1

Five primitive root multipliers for the prime-modulus 31 random number g3 enerator X.i+,l, = AX . mod 2 -1 have been i subjected to a battery of runs tests and serial tests for pairs and triples. Recommendations regarding these multipliers are made. Interesting results regarding the relative timings of the multipliers are presented. We also give results for the generators with these multipliers after they have been self-shuffled. A case where self-shuffling produced adverse results is also presented.http://archive.org/details/empiricaltestsof00learN

Statistical tests of some widely used and recently proposed uniform random number generators

Several widely used uniform random number generators have been extensively subjected to three commonly used statistical tests of uniformity and randomness. The object was i) to examine the power of these statistical tests to discriminate between "good" and "bad" random number generators, ii) to correlate these results with recently proposed mathematical characterizations of random number generators which might also be useful in such a discrimination, and iii) to examine the effect of shuffling on the random number generators . Briefly the results show that the commonly used runs test has virtually no power to discriminate between "good" and "bad" generators, while serial tests perform better. Also shuffling does help, although much more needs to be done in this area. And finally, there is some utility to the mathematical characterizations, but many unanswered questions.http://archive.org/details/statisticaltests00lea

Modeling the Complexities of Water, Hygiene, and Health in Limpopo Province, South Africa

Researchers have long studied the causes and prevention strategies of poor household water quality and early childhood diarrhea using intervention-control trials. Although the results of such trails can lead to useful information, they do not capture the complexity of this natural/engineered/social system. We report on the development of an agent-based model (ABM) to study such a system in Limpopo, South Africa. The study is based on four years of field data collection to accurately capture essential elements of the communities and their water contamination chain. An extensive analysis of those elements explored behaviors including water collection and treatment frequency as well as biofilm buildup in water storage containers, source water quality, and water container types. Results indicate that interventions must be optimally implemented in order to see significant reductions in early childhood diarrhea (ECD). Household boiling frequency, source water quality, water container type, and the biofilm layer contribution were deemed to have significant impacts on ECD. Furthermore, concurrently implemented highly effective interventions were shown to reduce diarrhea rates to very low levels even when other, less important practices were suboptimal. This technique can be used by a variety of stakeholders when designing interventions to reduce ECD incidences in similar settings