title: Tracking battery state-of-charge in a continuous use off-grid electricity system

authors: Apperley, Mark

subjects: computer science

abstract: The growing importance of batteries in the delivery of primary energy, for example in electric vehicles and isolated off-grid electricity systems, has added weight to the demand for simple and reliable measures of a battery’s remaining stored energy at any time. Many approaches to estimating this battery state-of-charge exist, ranging from those based on a full appreciation of the chemistry and physics of the storage and delivery mechanisms used, and requiring extensive data on which to base an estimate, to the naïve and simple, based only, for example, on the terminal voltage of the battery. None, however, is perfect, and able to deliver a simple percentage-full figure, as in a fuel gauge. The shortcomings are due to a range of complicating factors, including the impact of rate of charge, rate of discharge, battery aging, and temperature, to name just some of these.
This paper presents a simple yet effective method for tracking state-of-charge in an off-grid electricity system, where batteries are in continuous use, preventing static parameter measurements, and where charge/discharge cycles do not necessarily follow an orderly sequence or pattern. A reliable indication of state-of-charge is, however, highly desirable, but need be only of fuel gauge precision, say to the nearest 12-20%. The algorithm described utilises knowledge of the past, and constantly adapts parameters such as charge efficiency and total charge capacity based on this knowledge, and on the occurrence of specific identifiable events such as zero or full charge.

text: Tracking battery state-of-charge in a continuous use off-grid electricity system The growing importance of batteries in the delivery of primary energy, for example in electric vehicles and isolated off-grid electricity systems, has added weight to the demand for simple and reliable measures of a battery’s remaining stored energy at any time. Many approaches to estimating this battery state-of-charge exist, ranging from those based on a full appreciation of the chemistry and physics of the storage and delivery mechanisms used, and requiring extensive data on which to base an estimate, to the naïve and simple, based only, for example, on the terminal voltage of the battery. None, however, is perfect, and able to deliver a simple percentage-full figure, as in a fuel gauge. The shortcomings are due to a range of complicating factors, including the impact of rate of charge, rate of discharge, battery aging, and temperature, to name just some of these.
This paper presents a simple yet effective method for tracking state-of-charge in an off-grid electricity system, where batteries are in continuous use, preventing static parameter measurements, and where charge/discharge cycles do not necessarily follow an orderly sequence or pattern. A reliable indication of state-of-charge is, however, highly desirable, but need be only of fuel gauge precision, say to the nearest 12-20%. The algorithm described utilises knowledge of the past, and constantly adapts parameters such as charge efficiency and total charge capacity based on this knowledge, and on the occurrence of specific identifiable events such as zero or full charge.

year: 2013-10

title: Introducing contrast and luminance normalisation to improve the quality of subtractive resolution merge technique

authors: Ashraf, Muhammad Salman

subjects: image fusion

abstract: Subtractive resolution merge (SRM) is a contemporary image fusion method that produces highly preserved spatial and spectral resolution. This method is limited to dual sensor platforms with specific band ratios between the high-resolution panchromatic image (HRPI) and the low-resolution multispectral image (LRMI). An additional problem with SRM is that some bands are over- or under-represented due to the normalisation function applied. This article provides two modifications that resolve these limitations. SRM builds a synthetic low-resolution panchromatic image (LRPISYN) from the weighted sum of the LRMI bands. This image is modified by using a spatially resampled HRPI instead. The second modification is the use of a contrast and luminance index for the normalising function. These two modifications are tested on QuickBird images (multispectral and panchromatic), as well as fusing SPOT-5 (Satellite Pour l'Observation de la Terre) multispectral image and an aerial photograph. The results show improved quantitative metrics and unsupervised classification compared with the standard SRM technique and other contemporary image fusion methods. Both of these modifications are grouped into a patent pending technique that is called contrast and luminance normalised fusion.

text: Introducing contrast and luminance normalisation to improve the quality of subtractive resolution merge technique Subtractive resolution merge (SRM) is a contemporary image fusion method that produces highly preserved spatial and spectral resolution. This method is limited to dual sensor platforms with specific band ratios between the high-resolution panchromatic image (HRPI) and the low-resolution multispectral image (LRMI). An additional problem with SRM is that some bands are over- or under-represented due to the normalisation function applied. This article provides two modifications that resolve these limitations. SRM builds a synthetic low-resolution panchromatic image (LRPISYN) from the weighted sum of the LRMI bands. This image is modified by using a spatially resampled HRPI instead. The second modification is the use of a contrast and luminance index for the normalising function. These two modifications are tested on QuickBird images (multispectral and panchromatic), as well as fusing SPOT-5 (Satellite Pour l'Observation de la Terre) multispectral image and an aerial photograph. The results show improved quantitative metrics and unsupervised classification compared with the standard SRM technique and other contemporary image fusion methods. Both of these modifications are grouped into a patent pending technique that is called contrast and luminance normalised fusion.

year: 2013

title: The experience of homemaking in unaffordable and precarious housing

authors: Barrett, Patrick

abstract: Housing is the platform on which people build their lives. The experience of homemaking in unaffordable and precarious housing (Barrett, P., Cram, F. & James, B, 2024) is a new monograph from the Affordable Housing for Generations programme. Across 110 pages, 10 housing researchers share experiences from different groups of people in Aotearoa, burdened by the insecurity of unaffordable housing. The findings show how institutional, social and market dynamics impacting on life circumstances can cause people to be in precarious housing situations. Yet people continue to love homemaking and being contributors to their communities. Reinforcing the pivotal nature of housing in supporting all peoples’ health and wellbeing, this research demonstrates how much more can be achieved through improving access to stable, affordable housing and by understanding what is at the heart of a home.

text: The experience of homemaking in unaffordable and precarious housing Housing is the platform on which people build their lives. The experience of homemaking in unaffordable and precarious housing (Barrett, P., Cram, F. & James, B, 2024) is a new monograph from the Affordable Housing for Generations programme. Across 110 pages, 10 housing researchers share experiences from different groups of people in Aotearoa, burdened by the insecurity of unaffordable housing. The findings show how institutional, social and market dynamics impacting on life circumstances can cause people to be in precarious housing situations. Yet people continue to love homemaking and being contributors to their communities. Reinforcing the pivotal nature of housing in supporting all peoples’ health and wellbeing, this research demonstrates how much more can be achieved through improving access to stable, affordable housing and by understanding what is at the heart of a home.

year: 2024