Blar i forfatter "Zaki, Rezgar"

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    • Drilling waste minimization in the Barents Sea 

      Zaki, Rezgar (Master thesis; Mastergradsoppgave, 2015-05-19)
      With the increasing demand for energy over recent decades, the Arctic region has become an interesting area for future oil and gas exploration and development. The Barents Sea has the most western position among the Arctic seas surrounding the coast of Western Russia and Northern Norway. In the recent years several oil and gas discoveries done in this area and the number of wells is steadily ...

    • A mixture frailty model for maintainability analysis of mechanical components: a case study 

      Zaki, Rezgar; Barabadi, Abbas; Garmabaki, Amir Hossein Soleiman; Nuri, Ali (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-07)
      Knowing the maintainability of a component or a system means that repair resource allocations, such as spare part procurement and maintenance training, can be planned and optimized more effectively. Repair data are often collected from multiple and distributed units in different operational conditions, which can introduce heterogeneity into the data. Part of such heterogeneity can be explained and ...

    • Observed and unobserved heterogeneity in failure data analysis 

      Zaki, Rezgar; Barabadi, Abbas; Barabady, Javad; Qarahasanlou, Ali Nouri (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-08)
      In reality, failure data are often collected under diffract operational conditions (covariates), leading to heterogeneity among the data. Heterogeneity can be classified as observed and unobserved heterogeneity. Un-observed heterogeneity is the effect of unknown, unrecorded, or missing covariates. In most reliability studies, the effect of unobserved covariates is neglected. This may lead to inaccurate ...

    • Performance Measurement System in complex environment: observed and unobserved risk factors 

      Zaki, Rezgar (Doctoral thesis; Doktorgradsavhandling, 2020-12-04)
      <p>World demand for energy leads industry to harvest energy in complex environment with harsh conditions and sensitive areas, such as the Arctic region – one of the last remaining wild places in the world – with potentially harmful consequences. Moreover, over the past few decades, the increasing trend of melting sea ice in the Arctic has provided increased access and has created new opportunities ...