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Investigate feasibility of utilising a neural-networked set of inertial measurement units to compensate for variations in motion of a commercial radio-controlled vehicle in a dryland agricultural context : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science at Lincoln University
No full textImage stabilisation is desired for efficient identification of objects in the path of a self-driving vehicle. The gyroscope and accelerometer of an inertial measurement unit (IMU) can be used to derive the movement of a vehicle, which can then be used by a rotation matrix to compensate for this movement, but a gyroscope has inherent “drift” errors, and while the accelerometer of an IMU is more accurate, it has a slower response time, which reduces the detection rate.
Various methods have been proposed to compensate for these sensor limitations.
Kalman filters are often used in industry to fuse gyroscope and accelerometer data to reduce the effects of drift, noise, and other gaussian-based errors but these are computationally intensive for the sort of lightweight processor that a radio-controlled car could be expected to power. A complementary filter such as Madgwick’s is a simpler and less processor-intensive solution with claims that the method is just as accurate. Both of these approaches are applied on a single IMU. Averaging multiple IMUs has been investigated and offers slight improvements. Well-trained neural networks also offer IMU compensation but are computationally and time expensive to train to generate a model however the application of previously-trained models is less intensive and is becoming common as processor power improves. There have been no investigations of using a neural network on multiple IMUs as of this time.
This project investigates if using a neural network of multiple IMUs reduces errors and enhances performance compared to a single IMU.
The Kalman filter is used as baseline control data and three neural network models (MLP, NARXNET and RBF) are compared against each other and a Madgwick complementary filter to investigate if using a neural network of multiple IMUs reduces errors and enhances performance compared to a single IMU in the context of establishing Euler angles of roll and pitch movement to stabilise a video feed of a consumer-level camera on a moving commercial off-the-shelf radio control vehicle. It is demonstrated that there is no statistically significant advantage in using multiple IMUs if these are kept in the same horizontal plane, that a minimum of a three-layer MATLAB NARXNET filter provides the equivalent accuracy of a Kalman filter with similar processing times, and that the Madgwick IECF6 complimentary filter, the radial basis factor neural network and multi-level perceptron neural network models are not fit for this purpose
The interactive effect of temperature and fertilizer types determines the dominant microbes in nitrous oxide emissions and the dicyandiamide efficacy in a vegetable soil
No full text. Dicyandiamide decreased N₂O emissions even under 40°C.
. Ammonia oxidizers and nirS were well adapted to 40°C in manured soils.
. Fungal nirK tolerated high temperature better in urea than manure treatment.
. Compared to nosZII, nosZI adapted to all temperature regardless of fertilization.
. nirS-denitrifier dominated N₂O emissions at high temperature in fertilized soil.
Heat waves associated with global warming and extreme climates would arouse serious consequences on nitrogen (N) cycle. However, the responses of the functional guilds to different temperatures, especially high temperature and the cascading effect on N₂O emissions remain unclear. An incubation study was conducted to examine the effect of different temperatures (20°C, 30°C, and 40°C) and fertilizer types (urea and manure) on N₂O-producers and N₂O-reducers, as well as the efficacy of dicyandiamide (DCD) on N₂O emissions in a vegetable soil. Results showed that ammonia oxidizers and nirS-type denitrifiers were well adapted to high temperature (40°C) with manure application, while the fungal nirK-denitrifiers had better tolerance with urea application. The nosZ clade I microbes had a strong adaptability to various temperatures regardless of fertilization type, while the growth of nosZ clade II group microbes in non-fertilized soil (control) were significantly inhibited at higher temperature. The N₂O emissions were significantly decreased with increasing temperature and DCD application (up to 60%, even at 40°C). Under high temperature conditions, fungal denitrifiers play a significant role in N-limited soils (non-fertilized) while nirS-type denitrifiers was more important in fertilized soils in N₂O emissions, which should be specially targeted when mitigating N₂O emissions under global warming climate
Packaging for the future and enzyme depolymerization
No full textMember of interdisciplinary research discussion panel: “Packaging for the Future
Reevaluating the concept of aging: Long-term stress adaptation as a key factor in yeast aging
No full textIt has been demonstrated that short-term stress can enhance cellular responses and promote longevity, whereas long-term stress shortens lifespan. Understanding the relationship between short-term and long-term stress could offer new insights into comprehending and modulating age-related diseases. In this study, we investigate this relationship using transcriptomic and metabolomic analyses in the yeast model system (Saccharomyces cerevisiae).
We employed three metabolic treatments: firstly, treating yeast cells with threshold levels of benzoic acid for 24 hours (Short-term [ST] Stressed Cells); secondly, treating yeast cells with threshold levels of benzoic acid for 500 hours, with sub-culturing every 24 hours (Long-term [LT] Stressed Cells); and thirdly, allowing the long-term stressed cells to grow for 16 hours without any benzoic acid (Recovered Cells).
Here, we propose that aging is an evolutionarily conserved cellular adaptation mechanism in response to long-term stress exposure. Under short-term stressed conditions, prominent lifespan-extending metabolites such as trehalose and metabolites linked to tumor suppression in humans, such as 5’-methylthioadenosine, were overexpressed. In contrast, LT Stressed Cells activated genes such as those responsible for epigenetic regulatory enzymes that govern the aging process, and secondary stress response genes, such as heat shock proteins (HSPs) which are associated with adaptation to cell damage but also often associated with aged cells. Chronological lifespan experiments showed that LT stressed cells lived a shorter lifespan compared to ST Stressed Cells. This suggests that the markers of aging (eg. HSPs, certain epigenetic regulators) are expressed in response to long-term stress to enable cell survival but have the long-term effect of reducing lifespan. In support of this hypothesis, we also show that genes exclusively activated in ST Stressed Cells are conserved solely in eukaryotes, while those significantly expressed in LT Stressed Cells (aging related) exhibit high conservation across all domains of life, with a majority having originated from bacteria hinting at the potential evolutionary benefit of aging
Lizard monitoring in the extended wildside, Banks Peninsula, Canterbury
No full textLong-term monitoring programs are important to document changes in populations over time and to determine what other factors, such as predator control, may be influencing any changes. There are current predator control goals on Banks Peninsula by Pest Free Banks Peninsula (PFBP) to eradicate stoats, feral cats, and possums by 2024 and to be nationally predator free by 2050. However, there is no point controlling pests if there isn’t parallel monitoring of vulnerable native species, such as lizards. Our study has two aims: (1) to establish baseline date for lizard populations in the Wildside area of Banks Peninsula, and (2) to contribute to ongoing long-term monitoring with biannual surveys in January and April. We targeted five lizard species: Woodworthia brunnea, Naultinus gemmeus, Oligosoma polychroma Clade 5, O. lineoocellatum and O. maccanni. Monitoring was done across three habitats (grass, rock and bush edge) using artificial cover objects (ACOs), tracking tunnels, a 50m walk, a 5-minute vegetation scan and opportunistic searches. Only two species, W. brunnea and Oligosoma sp., were observed during this survey. Our work showed that ACOs provided the most observations, especially for W. brunnea. Oligosoma sp. were less frequently observed, possibly due to being day active and not using shelter. The tracking tunnels showed mice to be the most abundant mammal (22-37% of tunnels), also occurring where lizards were detected in tunnels. Further effort is needed to monitor lizard species not observed in this study, as the lack of observations does not equate to their absence
Firm-level political risk and earnings opacity
No full textGiven the recent growing global uncertainties, firms have encountered increasing political risks and responded accordingly to avoid a negative impact on their performance. This study examines the impact of firm-level political risk on corporate earnings opacity among listed U.S. firms. Our empirical results reveal that higher firm-level political risk engenders greater corporate earnings opacity via three channels of market scrutiny, political proximity, and multiple business objectives. Further analyses show that politically risky firms are more prudent in earnings management when they are highly dependent on government spending. The results hold after a wide range of robustness tests. Our findings provide several implications for the management of earnings quality in response to increasing firm-level political risk in the U.S
Native vegetation structure, landscape features and climate shape non-native plant richness and cover in New Zealand native shrublands
No full textAim: Studies investigating the determinants of plant invasions rarely examine multiple factors and often only focus on the role played by native plant species richness. By contrast, we explored how vegetation structure, landscape features and climate shape non-native plant invasions across New Zealand in mānuka and kānuka shrublands. Location: New Zealand. Method: We based our analysis on 247 permanent 20 × 20-m plots distributed across New Zealand surveyed between 2009 and 2014. We calculated native plant species richness and cumulative cover at ground, understorey and canopy tiers. We examined non-native species richness and mean species ground cover in relation to vegetation structure (native richness and cumulative cover), landscape features (proportion of adjacent anthropogenic land cover, distance to nearest road or river) and climate. We used generalized additive models (GAM) to assess which variables had greatest importance in determining non-native richness and mean ground cover and whether these variables had a similar effect on native species in the ground tier. Results: A positive relationship between native and non-native plant species richness was not due to their similar responses to the variables examined in this study. Higher native canopy richness resulted in lower non-native richness and mean ground cover, whereas higher native ground richness was associated with higher native canopy richness. Non-native richness and mean ground cover increased with the proportion of adjacent anthropogenic land cover, whereas for native richness and mean ground cover, this relationship was negative. Non-native richness increased in drier areas, while native richness was more influenced by temperature. Main Conclusions: Adjacent anthropogenic land cover seems to not only facilitate non-native species arrival by being a source of propagules but also aids their establishment as a result of fragmentation. Our results highlight the importance of examining both cover and richness in different vegetation tiers to better understand non-native plant invasions
A post-pandemic age-friendly mega-city? Navigating Tokyo's urban challenges
No full textIntroduction
The Tokyo-Yokohama mega-city is confronting the twin challenges of demographic aging and urbanization. As Tokyo ages, more attention is required to evaluate and improve urban walkability, which is a key World Health Organization indicator of age-friendliness that supports physical activity and social participation.
Objective
This research aimed to systematically assess walkability in 10 super-aged neighborhoods across two growing cities in west Tokyo.
Methods
This mixed methods research incorporated population surveys, systematic walking audits, and streetscape photography. Assessment of walking behavior was undertaken among 1200 Tokyo residents aged 65 and older using the International Physical Activity Questionnaire. Walking audits of 10 super-aged neighborhoods in the Musashino and Mitaka were undertaken using the Microscale Audit of Pedestrian Streetscapes tool and a team of trained auditors. Audits charted the journey from older-adult housing to four typical walking destinations within 400m.
Results
In Tokyo, 30% of older adults are physically inactive and walking behavior has declined by up to 13% since the beginning of the COVID-19 pandemic. Walking audits of super-aged neighborhoods revealed statistically significant variations in urban conditions, with all locations scoring in poor-to-fair ranges in relation to international reference values. Prevailing challenges included discontiguous pedestrian infrastructure, limited traffic calming measures, trip hazards, land use constraints, and a lack of supportive urban amenities.
Conclusion
Implications for age-friendly planning will be discussed to inform targeted remediation of urban walking conditions for aging residents. The utility of grounded observational methods will also be addressed for elucidating interactions between aging, urban environment, and walking behavior
Scales of development for wheat and barley specific to either single culms or a population of culms
No full textAccurate assessment of plant development is essential for agronomic management and scientific research, and crop development scales with repeatable and reproducible protocols are required to achieve this. Development scales currently in use are ambiguous, subjective and qualitative, they do not describe all stages in a crop's lifecycle, they do not explicitly distinguish between culm-level and crop-level development, and they are incompatible with modern analytical and computational technologies. Here we propose two new scales of wheat and barley development: the Single Culm Development Scale (SCDS) to define progression through the lifecycle of an individual culm, and the Population of Culms Development Scale (PCDS) to identify the timing of stages and duration of phases within a crop canopy. These development scales merge and fill gaps within existing scales currently in use, describe development in terms that are unambiguous, objective and quantitative, and better interface with crop simulation models, automated image analysis and other computational tools and analytical methods. The SCDS and PCDS are paired with definitive protocols to measure each stage that were developed and tested using different operators in controlled environment and field experiment
Drone use in on-farm environmental compliance: An investigation of regulators’ perspectives
Get PDFFreshwater resources around the world are under increasing pressure from agricultural activities. As a result, regulatory frameworks around on-farm environmental compliance have become more complex. Consequently, farm plans which have been used in New Zealand to identify risks to and develop mitigation strategies for freshwater quality can be time consuming and costly to develop and monitor. Using semi-structured interviews, this study investigated the views of the regulators working in environmental policy and implementation on the use of drones to increase the efficiency of on-farm environmental compliance. Results show that drones can improve process robustness by providing an aerial view, and that they are quicker and safer to use on steeper contoured farms. However, there is confusion around the permissions required in order to capture footage, its ownership and storage, and who has access rights to the footage. This ambiguity in the implementation of environmental regulations can lead to uncertainty on the part of policy implementors around how to integrate drones in on-farm environmental compliance. In addition, positive relationships between farmers and compliance officers are needed in order for the benefits of drone use to be realised for on-farm environmental compliance purposes