The analysis of a recombinative hill-climber on H-IFF

Many experiments have proved that crossover is an essential search operator in evolutionary algorithms, at least for certain functions. However, the rigorous analysis of such algorithms on crossover-friendly functions is still in its infancy. Here, a recombinative hill-climber is analyzed on the crossover-friendly function hierarchical-if-and-only-if (H-IFF) introduced by Watson et al. (1998). The dynamics of this algorithm are investigated and it is proved that the expected optimization time equals /spl Theta/(n log n).     

Ma?nahmen zur Sicherstellung von Deutschlands Fettbedarf

Ohne Zusammenfassung     

A simplified correctness proof for a well-known algorithm computing strongly connected components

The computation of the strongly connected components of a directed graph is one of the fundamental algorithmic graph problems. Linear-time algorithms with simple implementations are known. Here a simplified correctness proof for one of these algorithms is presented.     

Outcome of 1000 consecutive clinic- and hospital-based cataract surgeries in a Danish county

PURPOSE: To evaluate the homogeneity and quality of cataract surgery in a Danish county. SETTING: Four private eye clinics and the Department of Ophthalmology, Hiller?d Hospital, Frederiksborg County, Denmark. METHODS: This prospective study comprised 1012 consecutive cases of age-related cataract; 48% of the surgeries were performed in the hospital and 52%, at 1 of 4 clinics. Demographic and clinical data were recorded on standardized data sheets at referral, surgery, and final refraction. Main outcome measures were change in best corrected visual acuity (BCVA), refractive power at final refraction, surgery-related complications, and waiting time for surgery and final refraction. RESULTS: The hospital group had greater dispersion of age (P < .001) and higher frequency of general health problems (P < .005) and glaucoma (P < .01) than the clinic group. Fifty-four percent of surgeries were by phacoemulsification and 46%, by extracapsular cataract extraction (ECCE). In general, phacoemulsification was prevalent at the hospital and ECCE at the clinics. No difference was found between groups in visual acuity at final refraction. Of all patients, 87.1% attained a BCVA of 0.5 or better and of the best cases, 96.2%. Zonule or capsule rupture with or without vitreous loss occurred more often in the hospital group (P < .05), while the incidence of postoperative complications was identical in the 2 groups. One cases of retinal detachment was found. Time from referral to final refraction was shorter at clinics, while waiting time from surgery to final refraction was shorter at the hospital (P < .001). CONCLUSION: Dividing cataract surgery between hospital and private clinics seems to be a satisfactory model for meeting the increasing demand for cataract surgery.     

The Theory of Zero-Suppressed BDDs and the Number of Knight's Tours

Zero-suppressed binary decision diagrams (ZBDDs) have been introduced by Minato [14–17] who presents applications for cube set representations, fault simulation, timing analysis and the n-queens problem. Here the structural properties of ZBDDs are worked out and a generic synthesis algorithm is presented and analyzed. It is proved that ZBDDs can be at most by a factor n + 1 smaller or larger than ordered BDDs (OBDDs) for the same function on n variables. Using ZBDDs the best known upper bound on the number of knight's tours on an 8 × 8 chessboard is improved significantly.