Evaluating hyperspectral imagery for mapping the surface symptoms of dryland salinity

Airborne hyperspectral imagery has the potential to overcome the spectral and spatial resolution limitations of multispectral satellite imagery for monitoring salinity at both regional and farm scales. In particular, saline areas that have good cover of salt tolerant plants are difficult to map with multispectral satellite imagery. Hyperspectral imagery may provide a more reliable salinity mapping method because of its potential to discriminate halophytic plant cover from non - halophytes. HyMap and CASI airborne imagery ( at 3m ground resolution ) and Hyperion satellite imagery ( at 30 resolution ) were acquired over a 140 sq km dryland agricultural area in South Australia, which exhibits severe symptoms of salinity, including extensive patches of the perennial halophytic shrub samphire ( Halosarcia pergranulata ), sea barley grass ( Hordeum marinum ) and salt encrusted pans. The HyMap and Hyperion imagery were acquired in the dry season ( March and February respectively ) to maximise soil and perennial vegetation mapping. The optimum time of year to map sea barley grass, an annual species, was investigated through spectral discrimination analysis. Multiple reflectance spectra were collected of sea barley grass and other annual grasses with an ASD Fieldspec Pro spectrometer during the September spring flush and in November during late senescence. Comparing spectra of different species in November attempted to capture the spectral differences between the late senescing sea barley grass and other annual grasses. Broad NIR and SWIR regions were identified where sea barley grass differs significantly from other species in November during late senescence. The sea barley grass was therefore shown to have the potential to be discriminated and mapped with hyperspectral imagery at this time and as a result the CASI survey was commission for November. Other salinity symptoms were characterised by collecting single field and laboratory spectra for comparison to image derived spectra in order to provide certainty about the landscape components that were to be mapped. Endmembers spectra associated with saltpans and samphire patches were extracted from the imagery using automated endmember generation procedures or selected regions of interest and used in subsequent partial unmixing. Spectral subsets were evaluated for their ability to optimise salinity maps. The saltpan spectra contained absorption features consistent with montmorillonite and gypsum. A single gypsum endmember from one image strip successfully mapped saltpans across multiple images strips using the 1750 nm absorption feature as the input to matched filter unmixing. The individual spectra of green and red samphire are dominated by photosynthetic vegetation characteristics. The spectra of green samphire, often seen with red tips, exhibit peaks in both green and red wavebands whereas the red samphire spectra only contain a significant reflectance peak in the visible red wavelength region. For samphire, Mixture Tuned Matched Filtering using image spectra, containing all wavelength regions, from known samphire patches produced the most satisfactory mapping. Output salinity maps were validated at over 100 random sites. The HyMap salinity maps produced the most accurate results compared to CASI and Hyperion. HyMap successfully mapped highly saline areas with a good cover of samphire vegetation at Point Sturt without the use of multitemporal imagery or ancillary data such as topography or PIRSA soil attribute maps. CASI and Hyperion successfully mapped saltpan, however, their samphire maps showed a poor agreement with field data. These results suggest that perennial vegetation mapping requires all three visible, NIR and SWIR wavelength regions because the SWIR region contains important spectral properties related to halophytic adaptations. Furthermore, the unconvincing results of the CASI sea barley grass maps suggests that the optimal sensor for mapping both soil and vegetation salinity symptoms are airborne sensors with high spatial and spectral resolution, that incorporate the 450 to 1450 nm wavelength range, such as HyMap. This study has demonstrated that readily available software and image analysis techniques are capable of mapping indicators of varying levels of salinity. With the ability to map symptoms across multiple image strips, airborne hyperspectral imagery has the potential for mapping larger areas covering sizeable dryland agriculture catchments, closer in extent to single satellite images. This study has illustrated the advantage of the hyperspectral imagery over traditional soil mapping based on aerial photography interpretation such as the NLWRA Salinity 2000 and the PIRSA soil landscape unit maps. The HyMap salinity maps not only improved mapping of saline areas covered with samphire but also provided salinity maps that varied spatially within saline polygons.Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006

Methods of evaluating the effects of coding on SAR data

It is recognized that mean square error (MSE) is not a sufficient criterion for determining the acceptability of an image reconstructed from data that has been compressed and decompressed using an encoding algorithm. In the case of Synthetic Aperture Radar (SAR) data, it is also deemed to be insufficient to display the reconstructed image (and perhaps error image) alongside the original and make a (subjective) judgment as to the quality of the reconstructed data. In this paper we suggest a number of additional evaluation criteria which we feel should be included as evaluation metrics in SAR data encoding experiments. These criteria have been specifically chosen to provide a means of ensuring that the important information in the SAR data is preserved. The paper also presents the results of an investigation into the effects of coding on SAR data fidelity when the coding is applied in (1) the signal data domain, and (2) the image domain. An analysis of the results highlights the shortcomings of the MSE criterion, and shows which of the suggested additional criterion have been found to be most important

2D Proactive Uplink Resource Allocation Algorithm for Event Based MTC Applications

We propose a two dimension (2D) proactive uplink resource allocation (2D-PURA) algorithm that aims to reduce the delay/latency in event-based machine-type communications (MTC) applications. Specifically, when an event of interest occurs at a device, it tends to spread to the neighboring devices. Consequently, when a device has data to send to the base station (BS), its neighbors later are highly likely to transmit. Thus, we propose to cluster devices in the neighborhood around the event, also referred to as the disturbance region, into rings based on the distance from the original event. To reduce the uplink latency, we then proactively allocate resources for these rings. To evaluate the proposed algorithm, we analytically derive the mean uplink delay, the proportion of resource conservation due to successful allocations, and the proportion of uplink resource wastage due to unsuccessful allocations for 2D-PURA algorithm. Numerical results demonstrate that the proposed method can save over 16.5 and 27 percent of mean uplink delay, compared with the 1D algorithm and the standard method, respectively.Comment: 6 pages, 6 figures, Published in 2018 IEEE Wireless Communications and Networking Conference (WCNC

Natural Science – an Enemy or an Ally of Theodicy? Some Methodological Remarks inspired by St. Thomas Aquinas’ Natural Theology

Since the emergence of modern scientific revolution two opposing trends have appeared which attempted to use the hypotheses formulated on the basis of the dynamically developing natural science. The first of them focuses not only on questioning the truths of revealed faith relying on the results of natural science but also on demonstrating the groundlessness of the conclusions reached before by purely rational reflection which indicated the existence of the Absolute Being within the framework of theodicy. In the case of the second trend, there are attempts to interpret selected scientific discoveries as a confirmation of the truths contained in supernatural Revelation, or to use them as premises on the basis of arguments proposed by theodicy. St. Thomas Aquinas who was able to combine revealed knowledge with the scientific knowledge of his time, creating their integral synthesis is frequently mentioned in this respect to justify the rightness of this aspiration. The article addresses several methodological questions which provide a more ordered approach to the aforementioned issues relying on the model proposed by the Angelic Doctor.Przyrodoznawstwo – wróg czy sprzymierzeniec teodycei? Kilka metodologicznych uwag na marginesie teologii naturalnej św. Tomasza z Akwinu Na przestrzeni stuleci, jakie minęły od czasu nowożytnej rewolucji naukowej, zaobserwować można próby wykorzystywania formułowanych na gruncie rozwijającego się dynamicznie przyrodoznawstwa hipotez, zmierzające w dwóch przeciwstawnych kierunkach. W przypadku pierwszego z nich, mamy do czynienia z dążeniem, by w oparciu o wyniki badań przyrodniczych nie tylko zakwestionować prawdy wiary objawionej, ale również wykazać niezasadność wniosków, do jakich prowadziła wcześniej czysto racjonalna refleksja, wskazująca na fakt istnienia Bytu Absolutnego, prowadzona w ramach teodycei. W przypadku drugiego, spotykamy dążenie, by interpretować wybrane odkrycia naukowe jako swego rodzaju potwierdzenie prawd zawartych w nadprzyrodzonym Objawieniu, bądź też wykorzystywać je w charakterze przesłanek na gruncie teodycealnej argumentacji. Celem uzasadnienia słuszności tego dążenia, nierzadko przywoływany zostaje autorytet św. Tomasza z Akwinu jako tego, który potrafił łączyć wiedzę objawioną z wiedzą naukową swoich czasów, tworząc ich integralną syntezę. W ramach artykułu podjętych zostaje kilka kwestii o charakterze metodologicznym, pozwalających – jak się wydaje – uniknąć błędów, jakie pociągać może za sobą realizacja tego dążenia

Beloved: Born of Sethe\u27s Slavery and Trauma

Toni Morrison’s Beloved introduces many characters who exhibit clear signs of trauma due to their past as African American slaves, however, one character in particular stands out: Sethe. Sethe’s life as a slave led her to experience and do horrendous things. The worst being the difficult and violent decision to murder her own child, Beloved, in an effort to prevent her child from being forced into slavery. Though Sethe survived her life as a slave, she was unable to focus on her future because of her past that consistently haunts her. Her trauma is portrayed in many different forms throughout the novel: trees, scars, time, and the ghost of Beloved herself. These symbols of trauma provide the reader with a glimpse of how trauma, specifically trauma created from the United States\u27 dark history in slavery, influences Sethe from moving on, and continues to manipulate her throughout the novel. I will be analyzing these portrayals of trauma and how they affect Sethe’s character throughout the novel.https://digitalcommons.usu.edu/fsrs2021/1072/thumbnail.jp