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Experimental Research Study of the Impact of Distribution Channels of Particular Categories of Spare Parts on the Vehicle Repair Time

Lewicki W.

Logistics and Transport

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2017

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Vol. 35, No. 3

67--74

EN

In today’s market reality, the information about the real time of the vehicle repair time has become an imperative of tremendous importance. In today’s market of repair services, both the service providers and customers care about the most precise determination of this time. Thus, in terms of increasing market availability to other categories of spare parts than those original ones, the process of properly defining the implementation of the repair service is becoming more and more important. The article focuses on the issue of the influence of the distribution channels of particular categories of spare parts on the vehicle repair time. Considerations are based on author’s simulations covering a comparative study of car repair periods depending on the applied category of spare parts. The purpose of the article is to answer the question, whether the applied category of spare parts in the process of the performed repair service affects the implementation of this service.

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

Walkowiak T., Pol M.

Journal of Polish Safety and Reliability Association

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2017

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Vol. 8, No. 1

167--174

EN

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.

3

Analiza przestrzenna utraty bezpieczeństwa dostaw wody jako element procedur zarządzania ryzykiem

Zimoch I., Paciej J.

Gaz, Woda i Technika Sanitarna

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2017

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Nr 4

159--162

PL

Zapewnienie dostawy wody o odpowiedniej jakości, w odpowiedniej ilości i pod odpowiednim ciśnieniem jest podstawowym zadaniem przedsiębiorstwa wodociągowego. Analiza lokalizacji awarii j wraz z czasem odnowy stanowi element procedury szacowania bezpieczeństwa dostaw wody i może wspomagać eksploatatora przy zarządzaniu SZW. Przestrzenna charakterystyka bezpieczeństwa dostaw wody winna być uwzględniana w procedurach wyznaczania reprezentatywnych miejsc kontroli, zapewniających rzetelną ocenę zakresu zmian parametrów jakości wody podczas jej transportu do konsumenta. Celem prezentowanych badań była analiza przestrzenna skutków awarii stanowiąca element wyznaczania obszarów wrażliwych w modelu oceny bezpieczeństwa dostaw wody.

EN

Providing water supply of appropriate quality, quantity and at suitable pressure level is a primary task of Water Supply Companies. Analysis of failure location together with the time of renewal is part of procedure for estimating safety of water supply and can be helpful for exploiter in management of WSS. Spatial characteristics of water supply safety should be taken into account in the procedures of determining the representative control points which provides a reliable assessment of the extent of changes of water quality parameters during transport to consumer. The aim of this study was the spatial analysis about effects of accidents as a part of designating sensitive areas in water supply safety model.

4

A repair time model of a web based system including administrator working hours

Walkowiak T.

Journal of Polish Safety and Reliability Association

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2016

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Vol. 7, No. 1

233--240

EN

The paper presents a web based system reliability analysis. We propose to model different types of faults (hardware one, software and security incidents) taking consideration only the effect of the failure, not the source of the fault. It is assumed that failure events are independent and the time to failure is exponential. Whereas the time to repair is not exponential since repair actions are taken only when administrators are at work. We assume that administrators are not working 24/7. The paper presents an algorithmic model of the repair time including administrator working hours. The model is used to estimate reliability parameters (mean time, standard deviation and 90th percentile of yearly down time) by a use of Monte-Carlo simulation. The numerical results are compared with results from the analytical model (Markov one) that assumes exponential distribution of all repair times. Results for two web exemplar web systems (with reliability model consisting of two and five states) show the range of error caused by the exponential distribution assumption.

5

Wpływ wybranych czynników na poziom nienaruszalności bezpieczeństwa (SIL)

Młynarski S., Pilch R., Kaczor G., Smolnik M., Szkoda M., Szybka J.

Journal of KONBiN

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2015

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No. 3 (35)

85--98

PL

Praca dotyczy problematyki bezpieczeństwa funkcjonalnego systemów technicznych. Przedstawiona charakterystyka obowiązującej w zakresie oceny bezpieczeństwa normy IEC 61508 jest wprowadzeniem do problemów związanych z metodyką wyliczeń poziomów nienaruszalności bezpieczeństwa SIL. Prezentowane w pracy wyliczenia parametrów i wskaźników niezawodności przeprowadzono dla potrzeb oceny wpływu czasu odnowy elementów systemu na poziom bezpieczeństwa SIL. Wyliczone wartości intensywności uszkodzeń oraz prawdopodobieństwa niebezpiecznego uszkodzenia, charakteryzują wrażliwość systemu na różne czasy odnowy oraz dla różnych struktur niezawodnościowych systemu. Wskaźniki charakteryzujące poziom bezpieczeństwa wyliczone dla systemów bez odnowy stanowią podstawę dla wykazania wpływu odnowy systemu na poziom nienaruszalności bezpieczeństwa systemu SIL.

EN

The presented paper concerns the functional safety problems of technical systems. The characteristics of safety assessment, described in IEC 61508 standard are an introduction to the problems associated with the methodology of the calculation of Safety Integrity Levels (SIL). The parameters obtained from reliability indicators, were calculated for the purpose of assessing the impact of repair time for the elements of a given system on the SIL. The calculated values of failure rate and the probability of dangerous failure show the sensitivity of the system at different time to repair values for various reliability-wise configurations. The indicators characterizing the safety level, calculated of the system with no repair time are the basis for demonstrating the influence of repair on the safety integrity level.

6

Problemy uszkadzalności rolniczych agregatów maszynowych w procesie produkcji rolniczej

Piekarski W.

Problemy Inżynierii Rolniczej

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1999

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R. 7, nr 4

53-60

PL

Przedstawiono analizę zagadnień związanych a wpływem czasu pracy ciągników rolniczych do pierwszego uszkodzena i między uszkodzeniami przy wybranych zabiegach agrotechnicznych, umożliwiających wyznaczenie średniego czasu bezawaryjnej pracy rolniczego agregatu maszynowego. Ponadto wykorzystując zebrane wyniki badań, obejmujące zestawianie liczbowe dotyczące czasu pracy i naprawy ciągników C355/360, wyliczono wybrane wskaźniki niezawodności ciągników.

EN

Paper analysed the duration of operation time of agricultural tractors until the first failure as well as the time beetween successive failures at selected agro-technical opeation. On such a basis the average times of failure-free operation were determined for the field machine sets. Furthermore, by using the investigation results quantifying the operation time and repair C355/360 tractors, the reliability indices for these tractors were calculated.