Ontologies play an important role in applications related to knowledge management, natural language processing, information retrieval, etc. As a result, a large number of ontologies have been developed rapidly. Once an ontology is created, it can be used by many different applications. Such applications may use the entire ontology or only a part of it. Furthermore, they may use a part of the ontology and then extend it by adding more knowledge. Since ontologies which are used by different organisations may be related, there is a need to check these relationships. This paper presents an algorithm that compares two ontologies to determine their relationship. A semantic web service discovery application is introduced to highlight the motivation of the algorithm.

The current article is concerned with the interaction of Rayleigh waves with surface defects of arbitrary shape in a homogeneous, isotropic, linearly elastic half-space. Using a linear superposition principle, the interaction generates a scattered field which is equivalent to the field radiated from a distribution of horizontal and vertical tractions on the surface of the defect. These tractions are equal in magnitude but opposite in sign to the corresponding tractions obtained from the incident wave. The scattered field is then computed as the superposition of the displacements radiated from the tractions at every point of the defect surface using the reciprocity theorem approach. The far-field vertical displacements are compared with calculations obtained by the boundary element method (BEM) for circular, rectangular, triangular and arbitrary-shaped defects. Comparisons between the theoretical and BEM results, which are graphically displayed, are in excellent agreement. It is also discussed the limitations of the proposed approximate theory.

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Current treatment of complicated calculous biliary disease typically involves a two-step procedure consisting of pre- or post-operative endoscopic retrograde cholangiopancreatography (ERCP) followed by laparoscopic cholecystectomy (LC). This practice creates drawbacks as there is the need for two anesthesia inductions and longer hospital stay. The combination of LC and ERCP (LC + ERCP) for patients with cholecysto-choledocholithiasis has shown safety advantages, reducing anesthesia inductions and bringing high efficiency. This is a retrospective case series implemented at the Department of General Surgery - Hanoi Medical University Hospital between March 2020 and July 2022. In total, 44 patients met the criteria of this study. The average age of the cohort was 55.43 ± 18.12 years. The mean operating times of ERCP and LC were 58.05 ± 20.10 min and 54.09 ± 23.80 min, respectively. There was one intra-operative adverse event and no conversion. The mean hospital stay was 3.95 ± 2.28 days, and the rate of stones clearance was 100 per cent. LC combine ERCP in a single setting is a safe, effective procedure in treating cholecysto-choledocholithiasis.

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