Target Localization Accuracy Gain in MIMO Radar Based Systems

This paper presents an analysis of target localization accuracy, attainable by the use of MIMO (Multiple-Input Multiple-Output) radar systems, configured with multiple transmit and receive sensors, widely distributed over a given area. The Cramer-Rao lower bound (CRLB) for target localization accuracy is developed for both coherent and non-coherent processing. Coherent processing requires a common phase reference for all transmit and receive sensors. The CRLB is shown to be inversely proportional to the signal effective bandwidth in the non-coherent case, but is approximately inversely proportional to the carrier frequency in the coherent case. We further prove that optimization over the sensors' positions lowers the CRLB by a factor equal to the product of the number of transmitting and receiving sensors. The best linear unbiased estimator (BLUE) is derived for the MIMO target localization problem. The BLUE's utility is in providing a closed form localization estimate that facilitates the analysis of the relations between sensors locations, target location, and localization accuracy. Geometric dilution of precision (GDOP) contours are used to map the relative performance accuracy for a given layout of radars over a given geographic area.Comment: 36 pages, 5 figures, submitted to IEEE Transaction on Information Theor

Prevalence and socio-demographic predictors of food insecurity in Australia during the COVID-19 pandemic

The COVID-19 pandemic has exacerbated economic vulnerabilities and disrupted theAustralian food supply, with potential implications for food insecurity. This study aims to describe theprevalence and socio-demographic associations of food insecurity in Tasmania, Australia, during theCOVID-19 pandemic. A cross-sectional survey (deployed late May to early June 2020) incorporatedthe U.S. Household Food Security Survey Module: Six-Item Short Form, and fifteen demographicand COVID-related income questions. Survey data (n = 1170) were analyzed using univariate andmultivariate binary logistic regression. The prevalence of food insecurity was 26%. The adjusted oddsof food insecurity were higher among respondents with a disability, from a rural area, and living withdependents. Increasing age, a university education, and income above $80,000/year were protectiveagainst food insecurity. Food insecurity more than doubled with a loss of household income above25% (Adjusted Odds Ratio (AOR): 2.02; 95% CI: 1.11, 3.71; p = 0.022), and the odds further increasedwith loss of income above 75% (AOR: 7.14; 95% CI: 2.01, 24.83; p = 0.002). Our results suggest thatthe prevalence of food insecurity may have increased during the COVID-19 pandemic, particularlyamong economically vulnerable households and people who lost income. Policies that supportdisadvantaged households and ensure adequate employment opportunities are important to supportAustralians throughout and post the COVID-19 pandemic

Definitions, sources and self-reported consumption of regionally grown fruits and vegetables in two regions of Australia

Regional food systems are complex networks, with numerous retail sources that underpin a local economy. However, evidence is limited regarding how consumers define, identify, and source regionally grown fresh fruits and vegetables (RGFFV). A cross-sectional study was conducted in Tasmania (TAS) and South Western Australia (SWA) to compare how RGFFV are defined, identified and sourced by consumers, including self-reported consumption of selected RGFFV. Survey data were analyzed using the Chi-square test and t-tests. Results (TAS n = 120, SWA n= 123) identified that consumers had mixed perceptions of how RGFFV are defined, including produce sold at farmers markets, or grown within their region (TAS/SWA). RGFFV were commonly identified using product labelling (55% TAS, 69% SWA; p > 0.05). Respondents reported frequently shopping for RGFFV at major supermarkets, with more TAS respondents shopping weekly in comparison to SWA respondents (67% vs. 38%; p p = 0.012). The major RGFFV consumed were root vegetables and apples/pears, but consumers were frequently unsure about the produce's provenance. Our findings indicate multiple opportunities to improve consumption of fresh, regional produce in TAS and SWA, which may positively impact regional economic growth and community health

Australian consumer perceptions of regionally grown fruits and vegetables: importance, enablers, and barriers

Fresh fruits and vegetables are a cornerstone of a balanced diet; their consumption has health, environmental, ethical, and economic implications. This pilot study aimed to: (i) measure fruit and vegetable consumption; (ii) understand consumer perceptions of the perceived importance of regionally grown fresh fruit and vegetables (RGFFV); and (iii) identify the barriers and enablers of access and consumption of RGFFV. The study took place in Tasmania (TAS) and South Western Australia (SWA). A 54-item survey included questions relating to purchasing and consumption patterns; barriers and enablers related to access and consumption of RGFFV; and sociodemographic information. Survey data were analyzed using Chi-square test and binary logistic regression. A total of n = 120 TAS and n = 123 SWA adult respondents participated. SWA respondents had higher intakes of fruit (p p < 0.001). Almost all respondents (97%) rated purchasing of RGFFV as important. Top enablers included produce freshness (97%), and to financially support local farmers (94%) and the local community (91%). Barriers included limited seasonal availability of the produce (26%), the belief that RGFFV were expensive (12%) and food budgetary constraints (10%). Recommendations include broader marketing and labelling of seasonal RGFFV; increasing 'buy local' campaigns; consumer information about how RGFFV benefits producers and communities; and pricing produce according to quality

Co-design of a personalised digital intervention to improve vegetable intake in adults living in Australian rural communities

\ua9 2024, The Author(s). Background: Diets low in vegetables are a main contributor to the health burden experienced by Australians living in rural communities. Given the ubiquity of smartphones and access to the Internet, digital interventions may offer an accessible delivery model for a dietary intervention in rural communities. However, no digital interventions to address low vegetable intake have been co-designed with adults living in rural areas. This paper describes the co-design of a digital intervention to improve vegetable intake with rural community members and research partners. Methods: Active participants in the co-design process were adults ≥ 18 years living in three rural Australian communities (total n = 57) and research partners (n = 4) representing three local rural governments and one peak non-government health organisation. An iterative co-design process was undertaken to understand the needs (pre-design phase) and ideas (generative phase) of the target population. Eight online workshops and a community survey were conducted between July and December 2021. The MoSCoW prioritisation method was used to help participants identify the ‘Must-have, Should-have, Could-have, and Won’t-have or will not have right now’ features and functions of the digital intervention. Workshops were transcribed and inductively analysed using NVivo. Convergent and divergent themes were identified between the workshops and community survey to identify how to implement the digital intervention in the community. Results: Consensus was reached on a concept for a digital intervention that addressed individual and food environment barriers to vegetable intake, specific to rural communities. Implementation recommendations centred on (i) food literacy approaches to improve skills via access to vegetable-rich recipes and healthy eating resources, (ii) access to personalisation options and behaviour change support, and (iii) improving the community food environment by providing information on and access to local food initiatives. Conclusions: Rural-dwelling adults expressed preferences for personalised intervention features that can enhance food literacy and engagement with community food environments. This research will inform the development of the prototyping (evaluation phase) and feasibility testing (post-design phase) of this intervention

Target Localization Accuracy and Multiple Target Localization: Tradeoff in MIMO Radars

This paper undertakes the study of localization performance of multiple targets in coherent MIMO radar systems with widely spread elements. MIMO radar systems with coherent processing and a single target were shown to benefit from a coherency and spatial advantages. The first is proportional to the ratio of the signal carrier frequency to the effective bandwidth, while the latter provides a gain proportional to the product of the number of transmitting and receiving sensors. In the current study, the model in extended to the estimation accuracy of multiple targets. The Cramer-Rao lower bound (CRLB) for the multiple targets localization problem is derived and analyzed. The localization is shown to benefit from coherency advantage. The tradeoff between target localization accuracy and the number of targets that can be localized is shown to be incorporated in the spatial advantage term. An increase in the number of targets to be localized exposes the system to increased mutual interferences. This tradeoff depends on the geometric footprint of both the sensors and the targets, and the relative positions of the two. Numerical analysis of some special cases offers an insight to the mutual relation between a given deployment of radars and targets and the spatial advantage it presents