Purdue University Graduate School
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Optimal Policy for Nested Task Interruptions in a Workflow Process

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posted on 2019-01-17, 21:18 authored by Haitham H. SalehHaitham H. Saleh
Interruptions are the phenomena that exist and appear in many places in life; they appear everywhere in every kind of activities either in doing personal activities on a daily basis or in doing complicated activities and processes in complex systems in industries.

The role and the effect of interruptions have begun to appear a lot significantly in the industries in the last few years especially the ones that related to the task or job interruptions in businesses that affect directly to the flow process of the work. It is important to reference that the interruptions can be found in many different formats depending on the work environments. Interruptions are considered as a request for a change in process, job, think, direction, move or just for a short period of pause; these interruptions have the potential to carry treasured information that can allow people to control and manage activities in the incredibly dynamic environment successfully. This control obligation is universal in many different work environments ranging from office work to a more complicated and complex world of industries and businesses. Thus, interruptions have the potential for a tremendous positive impact on work success or the potential for a significant negative impact on work success. Industries hypothesize this interruption as a useful source of valuable information to improve the workplace and flow process. Increasing the frequency of interruptions can lead to increasing the magnitude of information obtainable from a highly dynamic activities environments.

Consequently, that leads to improving the coordination between people for the entire organization. However, this possible enhancement and improvement in performance and workflow process of work, utilizing the insight information from interruptions, has shown to be extremely problematic and challenging. The efficacy of the information attained from interruptions is relevant to the ongoing revolution of the workflow process.

In this dissertation, we divide the research study into two different phases. In the initial phase, we study the workflow process interruptions from the standpoint of human subject experimentation to understand, explore, comprehend, and exploit interruptions phenomena while doing a particular task. This phase leads us to comprehend and learn whether or not the workflow process interruptions affect on task performance, transitional lag time, interruption lag time, and resumption lag time regarding the range and the level of interruptions. We conduct experiments in two stages, and we use factorial designs in these experiments. In the second stage of this phase, we use the obtained information from the first stage to design the experiment for this stage. Subsequently, the experiment is complete and proposes new policy regulations for the workflow processes under the occurrence of the nested interruptions circumstances.

In the second phase of the dissertation, we study the workflow process interruptions from the standpoint of a simulation model. The apparent primary goal of this phase is to understand and comprehend the effect of the workflow process interruptions in the context of various policies. In this study, we compare, test, and evaluate the new proposed policy compared to the current practice of handling interruptions when nested interruptions exist and occur. As a result, the proposed policy improved the workflow process by a substantial and noticeable amount of time-saving in total completion time for the workflow process.


Degree Type

  • Doctor of Philosophy


  • Industrial Engineering

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Dr. Steven Landry

Additional Committee Member 2

Dr. Hong Wan

Additional Committee Member 3

Dr. Brandon Pitts

Additional Committee Member 4

Dr. Byung Cheol (Bruce) Lee

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