THE DESIGN OF A POWER SYSTEM FOR A WIRELESS SENSOR NETWORK FOR LONG-TERM OPERATION

Wireless sensor networks (WSNs) have shown wide applicability to many fields including monitoring of environmental, civil, and industrial settings. WSNs however are resource constrained by many competing factors that span their hardware, software, and networking. One of the central resource constrains is the charge consumption of WSN nodes. With finite energy supplies, low charge consumption is needed to ensure long lifetimes and success of WSNs. This thesis details the design of a power system to support long-term operation of WSNs. The power system’s development occurs in parallel with a custom WSN from the Queen’s MEMS Lab (QML-WSN), with the goal of supporting a 1+ year lifetime without sacrificing functionality. The final power system design utilizes a TPS62740 DC-DC converter with AA alkaline batteries to efficiently supply the nodes while providing battery monitoring functionality and an expansion slot for future development. Testing tools for measuring current draw and charge consumption were created along with analysis and processing software. Through their use charge consumption of the power system was drastically lowered and issues in QML-WSN were identified and resolved including the proper shutdown of accelerometers, and incorrect microcontroller unit (MCU) power pin connection. Controlled current profiling revealed unexpected behaviour of nodes and detailed current-voltage relationships. These relationships were utilized with a lifetime projection model to estimate a lifetime between 521-551 days, depending on the mode of operation. The power system and QML-WSN were tested over a long term trial lasting 272+ days in an industrial testbed to monitor an air compressor pump. Environmental factors were found to influence the behaviour of nodes leading to increased charge consumption, while a node in an office setting was still operating at the conclusion of the trail. This agrees with the lifetime projection and gives a strong indication that a 1+ year lifetime is achievable. Additionally, a light-weight charge consumption model was developed which allows charge consumption information of nodes in a distributed WSN to be monitored. This model was tested in a laboratory setting demonstrating +95% accuracy for high packet reception rate WSNs across varying data rates, battery supply capacities, and runtimes up to full battery depletion.

NON-FULL-TIME COLLEGE PROFESSORS: A NARRATIVE INQUIRY INTO THE NON-FULL-TIME FACULTY ROLE

The rate of non-full-time faculty members has increased rapidly over the last decade (Louis, 2009; MacKay, 2014; Meranze & Newfield, 2013), as the post-secondary landscape of fluctuating enrolment, fiscal and operational challenges, and the requirement to hire specialized skill sets have required institutions to rely heavily on this demographic. In the Ontario Colleges of Applied Arts and Technology (CAATs) system, institutions have tried to preserve and enhance educational quality with fewer resources through greater reliance on non-full-time faculty. The purpose of this study was to explore the perceptions and experiences of teaching and support of non-full-time faculty at one Eastern Ontario college. Employing a narrative inquiry methodology, data were collected from four participants through their writing three individual letters at the end of each month and participating in one interview at the end of the contract period. The data were analyzed and coded. This analysis revealed five themes: motivation, connection and engagement, compensation, teaching and development, and performance evaluation. Differences in the participants’ perceptions tended to reflect divergences across career stage: retired versus early career. The compensation package provided to non-full-time faculty was considered inadequate for those in the early career stage, especially comparing it to that of full-time faculty. In addition, the amount of previous teaching experience was an important indicator for the appropriate level of teaching resources and support provided by the institution. The newer faculty members required a higher level of support to combat feelings of role isolation. The temporary nature of the role made it difficult to establish a feeling of a strong connection to the institution and subsequently opportunities to engage further to deepen the relationship. Despite these differences across participants, autonomous motivators were consistent across all narratives, as participants expressed their desire to teach and share their knowledge to help students achieve their goals. Participants concluded their narratives by sharing future advice for faculty interested in pursuing the role. The narratives provided areas for improvement that would help increase the level of job satisfaction for non-full-time college faculty members: (a) establishing a more thorough performance evaluation process to align with institutional supports, (b) offering more diverse teaching resources to better prepare faculty and enhance teaching practices, (c) overhauling the compensation package to better recognize the amount of time and effort spent in the role and aligning with the compensation provided to full-time faculty, and (d) including rewards and incentives as part of the compensation package to enhance the level of commitment and availability for the role. These changes might well increase the job satisfaction and improve the retention of non-full-time faculty members.