On the bit-parallel simulation of the nondeterministic Aho-Corasick and suffix automata for a set of patterns

In this paper we present a method to simulate, using the bit-parallelism technique, the nondeterministic Aho-Corasick automaton and the nondeterministic suffix automaton induced by the trie and by the Directed Acyclic Word Graph for a set of patterns, respectively. When the prefix redundancy is nonnegligible, this method yields-if compared to the original bit-parallel encoding with no prefix factorization-a representation that requires smaller bit-vectors and, correspondingly, less words. In particular, if we restrict to single-word bit-vectors, more patterns can be packed into a word. We also present two simple algorithms, based on such a technique, for searching a set P of patterns in a text T of length n over an alphabet @S of size @s. Our algorithms, named Log-And and Backward-Log-And, require O(([email protected])@?m/[email protected]?)-space, and work in O([email protected]?m/[email protected]?) and O([email protected]?m/[email protected]?l"m"i"n) worst-case searching time, respectively, where w is the number of bits in a computer word, m is the number of states of the automaton, and l"m"i"n is the length of the shortest pattern in P

A compact representation of nondeterministic (suffix) automata for the bit-parallel approach

AbstractWe present a novel technique, suitable for bit-parallelism, for representing both the nondeterministic automaton and the nondeterministic suffix automaton of a given string in a more compact way. Our approach is based on a particular factorization of strings which on the average allows to pack in a machine word of w bits automata state configurations for strings of length greater than w. We adapted the Shift-And and BNDM algorithms using our encoding and compared them with the original algorithms. Experimental results show that the new variants are generally faster for long patterns

Longest common substrings with k mismatches

The longest common substring with k-mismatches problem is to find, given two strings S-1 and S-2, a longest substring A(1) of S-1 and A(2) of S-2 such that the Hamming distance between A(1) and A(2) isPeer reviewe

How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons

COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice