The impact of administrator working hours on the reliability of the Centre of Language Technology

The paper presents reliability analysis of CLARIN-PL Centre of Language Technology (CLT). The CLT is a Polish part of the language technology infrastructure developed by CLARIN project. The main goal of which is to support researchers in humanities and social sciences. The infrastructure is a complex computer system that enables combining language tools with language resources into processing chains. Authors present the system structure, analyse types of faults and define the CLT reliability model. The model takes into account the fact the time gap, between the failure and the repair of the system is not exponential since repair actions are taken only when administrators are at work (assuming that administrators are not working 24/7). The model is used to estimate reliability metrics (mean time and 90th percentile of relative down time and relative partial operational time) by a use of Monte-Carlo simulation. Moreover, analysis of possible improvement in the CLT organisation and its influence on the estimated metrics is given.