Tuwhera Research Repository

The Tuwhera Research Repository provides sustainable open access and archiving to a broad range of AUT produced research - theses, research outputs and datasets.

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Access status: Open Access ,
Teaching Technical University Subjects in English to Mixed-Language Student Classroom
(Czech Technical University in Prague, 2026-07-31) Poshdar, Mani; Tomek, Radan; Yamamoto, Gonca Telli
This study examined the authors' experiences with teaching technical material in English to international students using mixed-language classrooms. The authors have identified both effective and ineffective ways of teaching these types of courses. Through systematic classroom observation and analysis, the authors identified what students had learned from each course taught entirely in English. In response to the complexities of implementing English Medium Instruction (EMI) in multiple languages and at multiple levels of academic studies, this longitudinal study tested and evaluated the use of the Language Responsive Delivery Model (LRDM). This model was used throughout all undergraduate and postgraduate Construction Management classes in four countries: the Czech Republic, New Zealand, Turkey, and the USA. Based on an Action Research methodology, the LRDM has three components of iterative phases as follows: prior to class delivery of the instructional materials including preliminary language assessments and a list of technical vocabulary terms; during class delivery using the "pause – paraphrase – probe" method and collecting data by minute-paper evaluations; and after class delivery, assessing learning outcomes through multimodal formats. This study explored how students with various levels of language proficiency affect their ability to comprehend instruction. Due to the differences in reading abilities among students, the authors found that traditional written exams were subject to biases related to reading literacy. The results indicated that using verbal testing and developing well-crafted rubrics for evaluating student performance provided a more equitable way of assessing a student's technical knowledge rather than their ability to communicate in English. The authors also outlined common pedagogical obstacles experienced by educators and suggested scalable approaches for universities. Lastly, the authors synthesized possible developmentally oriented directions and emerging trends that may enhance the model's long-term viability globally in engineering education such as integrating generative AI, large language models, micro-credential systems, and immersive digital twin labs.
Access status: Open Access ,
State-Dependent Merit-Order Effects in a Hydro-Dominated Market: Conditioning Variable-Renewable Price Suppression on the Marginal Fuel Regime in New Zealand
(MDPI AG, 2026-08-10) Hassan, Ahmed; Prasad, Krishnamachar; Kilby, Jeff
The merit-order effect (MOE), the suppression of wholesale prices by zero-marginal-cost variable renewable energy (VRE), is typically estimated as a single average coefficient per market. In a hydro-dominated system, the price-setting technology alternates between hydro and thermal plants, so the MOE should depend on the operating state. Using New Zealand nodal data, a baseline panel model first reproduces a published 2011–12 seasonal benchmark to within NZ$0.22/megawatt-hour (MWh). A model conditioning the VRE coefficient on reservoir storage (2015–24, 245 nodes, 28,827 node-month observations from approximately 42 million half-hourly records) passes every in-sample diagnostic (within R2 = 0.81) yet fails out-of-sample and stability testing. The interaction adds no significant predictive value beyond a storage main effect (p = 0.15–0.22) and reverses sign across sub-periods (+58 to −51), an instability not attributable to collinearity. Replacing the storage level with the monthly thermal generation share, a dispatch-based proxy for the hydro-thermal regime, yields a stable, significant, out-of-sample-validated interaction (clustered t = 5.0, leave-one-month-out cross-validation gain +14.2%) that survives direct hydrological and demand controls, including a head-to-head test against a storage interaction. Identification rests on 120 monthly observations, since these regressors are system-wide. Price suppression is strongest in hydro-abundant months, at approximately NZ$5.8/MWh per 10% relative VRE increase, and attenuates toward zero as the thermal share rises, consistent with water-value pricing. A forward test on Jan 2025 to May 2026 data, which postdate model development, confirms the interaction’s predictive value (forward RMSE improvement +33%, wild cluster bootstrap p = 0.047). Re-estimation on the 2011–12 panel returns a weakly identified, directionally opposite interaction (bootstrap two-sided p = 0.053). The validated state dependence therefore characterises the 2015–24 market regime rather than a structurally invariant relationship.
Access status: Open Access ,
Design and Realization of a Frequency Reconfigurable Multimode Antenna for ISM, 5G-sub-6-GHz, and S-band Applications
(MDPI AG, 2021-02-11) Ghaffar, Adnan; Li, Xue Jun; Awan, Wahaj Abbas; Iffat Naqvi, Syeda; Hussain, Niamat; Seet, Boon-Chong; Alibakhshikenari, Mohammad; Falcone, Francisco; Limiti, Ernesto
This paper presents the design and realization of a compact size multimode frequency reconfigurable antenna. The antenna consists of a triangular-shaped monopole radiator, originally inspired from a rectangular monopole antenna. Slots were utilized to notch the desired frequency while the PIN diodes were utilized to achieve frequency reconfigurability. The antenna can operate in wideband, dual-band, or tri-band mode depending upon the state of the diodes. To validate the simulation results, a prototype was fabricated, and various performance parameters were measured and compared with simulated results. The strong agreement between simulated and measured results along with superior performance as compared to existing works in the literature makes the proposed antenna a strong candidate for ISM, 5G-sub-6 GHz, and S-band applications.
Access status: Open Access ,
Recent Advancement in the Design of Mixers for Software Defined Radios
(Wiley, 2021-11-08) Mehta, Shilpa; Li, Xue Jun; Donelli, Massimo
The implementation of software-defined radio necessitates a versatile radio frequency (RF) front-end that can support multiple standards in different frequency bands. This article presents the state-of-the-art multiband and wideband mixers in the context of different receiver architectures suitable for software-defined radio (SDR). Wideband and multiband mixer designs reported in the literature are categorized on the basis of their circuit architecture. This study tabulates the results of mixer designs with an emphasis on noise figure (NF), conversion gain (CG), linearity, and image rejection ratio. The best parameters reported in the comparison are 68–84 dB of CG, 3.2 dB of NF, 2.5 mW of power consumption, 12.5 dBm of third-order input intercept point, and 0.015 mm<sup>2</sup> of area at different frequencies. The study also discusses the design challenges and techniques to overcome those issues. The article concludes with the summary and prospective developments for SDR architectures.
Access status: Open Access ,
Person–Supervisor Fit and Proactive Behavior and Unethical Behaviors
(Towarzystwo Naukowe KUL, 2021-02-16) Korulczyk, Tomasz; Cooper-Thomas, Helena D
This study examined how person–supervisor fit is related to employees’ proactive behavior and unethical behavior towards the organization. The study involved 321 employees representing various sectors in Poland. The participants completed the Person–Supervisor Fit Scale, Proactive Behavior Scale, and the Unethical Behavior Questionnaire. Results show that a supplementary fit is weakly and positively related to proactive behavior but is not related to complementary fit. Surprisingly, supplementary fit is weakly but positively related to unethical behavior, while complementary fit from a needs–resources perspective is weakly and negatively associated with unethical behavior. Conclusions may be applied to organizational settings challenged by the problem of employee unethical behavior and their low proactivity in the context of person–supervisor congruence.