Lossless and Near-Lossless Compression Algorithms for Remotely Sensed Hyperspectral Images.

Rapid and continuous advancements in remote sensing technology have resulted in finer resolutions and higher acquisition rates of hyperspectral images (HSIs). These developments have triggered a need for new processing techniques brought about by the confined power and constrained hardware resources aboard satellites. This article proposes two novel lossless and near-lossless compression methods, employing our recent seed generation and quadrature-based square rooting algorithms, respectively. The main advantage of the former method lies in its acceptable complexity utilizing simple arithmetic operations, making it suitable for real-time onboard compression. In addition, this near-lossless compressor could be incorporated for hard-to-compress images offering a stabilized reduction at nearly 40% with a maximum relative error of 0.33 and a maximum absolute error of 30. Our results also show that a lossless compression performance, in terms of compression ratio, of up to 2.6 is achieved when testing with hyperspectral images from the Corpus dataset. Further, an improvement in the compression rate over the state-of-the-art k2-raster technique is realized for most of these HSIs by all four variations of our proposed lossless compression method. In particular, a data reduction enhancement of up to 29.89% is realized when comparing their respective geometric mean values.

Physicians' Knowledge of the Systematic ABCDE Approach in Riyadh, Saudi Arabia.

Purpose: To evaluate physicians' knowledge of the ABCDE (Airway, Breathing, Circulation, Disability, Exposure) approach components. Methods: A cross-sectional study was conducted in 2023 using an online questionnaire in order to collect data about the knowledge of the ABCDE approach's components among physicians in different specialties in Riyadh, Saudi Arabia. Results: The number of participants were 165 in total and the median knowledge score for all participants was 15.0, with an associated interquartile range (IQR) of 10.0 to 20.0. Intensive Care Medicine had the highest median knowledge score of 19.0 (IQR: 12.0-21.0), followed by Internal Medicine at 17.0 (IQR: 13.0-20.0). Conversely, Cardiology and Anesthesiology showed lower scores, with medians of 8.0 (IQR: 4.0-10.0) and 7.5 (IQR: 4.0-13.5), respectively (p = 0.011). Senior Registrars demonstrated the highest median knowledge score of 20.0 (IQR: 14.0-22.0), while Fellows had the lowest at 8.5 (IQR: 7.0-13.0) (p < 0.001). Practicing for 10 to 15 years and more than 15 years having medians of 20.0 (IQR: 16.0-23.0) and 19.0 (IQR: 17.0-22.0), respectively. However, participants with less experience, working for less than 5 years, had a median score of 12.0 (IQR: 8.5-16.5) (p < 0.001). Conclusion: Knowledge scores of physicians representing various medical specialties found diverse levels regarding the ABCDE approach. Knowledge scores were significantly influenced by the primary area of practice, level of experience, and duration worked in the profession, highlighting the need for tailored training and education across different specialties and career stages. On the other hand, future studies should concentrate on finding new factors that influence practice adherence to the ABCDE approach and tying theoretical knowledge to clinical practice.

The practices of intravenous sodium bicarbonate therapy in neonatal intensive care units: A multi-country survey.

A common occurrence in the neonatal intensive care unit (NICU) is metabolic acidosis. Sodium bicarbonate (SB) has been widely used, but there is insufficient evidence on how SB affects neonates in NICUs with metabolic acidosis. The worsening of intracellular acidosis, the impairment of myocardial function, fluctuations in cerebral blood flow, and intracranial hemorrhage are some of the unfavorable effects of SB treatment in neonates that have been documented in the literature. This study aimed to explore neonatologists' practices for using intravenous SB (ISB) in NICUs. A multi-country survey was carried out in 2022 using an online questionnaire sent to neonatologists in various countries in order to gather information about the use of ISB in NICUs. A previously validated questionnaire was adapted and used in this study. The response rate was 67%. The findings show that 91.2% of neonatologists were using SB to correct metabolic acidosis in the NICU; 71.4% did not have written guidelines for using sodium bicarbonate. The majority of them (78.9%) reported that dosage is included in their guidelines for the use of ISB. The findings of this study emphasize the critical importance of providing guidelines in using ISB for managing metabolic acidosis in NICU to standardize procedures and reduce the use of potentially unsuitable and unsafe treatments, as it has been shown that 71.4% of neonatologists worldwide use sodium bicarbonate without guidelines.

Novel seed generation and quadrature-based square rooting algorithms.

The square root operation is indispensable in a myriad of computational science and engineering applications. Various computational techniques have been devised to approximate its value. In particular, convergence methods employed in this regard are highly affected by the initial approximation of the seed value. Research shows that the provision of an initial approximation with higher accuracy yields fewer additional iterations to calculate the square root. In this article, we propose two novel algorithms. The first one presents a seed generation technique that depends on bit manipulation and whose output is to be used as an initial value in the calculation of square roots. The second one describes a quadrature-based square rooting method that utilizes a rectangle as the plane figure for squaring. We provide error estimation of the former using the vertical parabola equation and employ a suitable lookup table, for the latter, to store needed cosine values. The seed generation approach produces a significant reduction in the number of iterations of up to 84.42% for selected convergence methods. The main advantages of our proposed square rooting algorithm lie in its high accuracy and in its requirement of just a single iteration. Our proposed algorithm also provides for lower computational latency, measured in the number of clock cycles, compared to Newton-Raphson's and Bakhshali's square rooting methods.

A Systematic Review of Hardware-Accelerated Compression of Remotely Sensed Hyperspectral Images.

Hyperspectral imaging is an indispensable technology for many remote sensing applications, yet expensive in terms of computing resources. It requires significant processing power and large storage due to the immense size of hyperspectral data, especially in the aftermath of the recent advancements in sensor technology. Issues pertaining to bandwidth limitation also arise when seeking to transfer such data from airborne satellites to ground stations for postprocessing. This is particularly crucial for small satellite applications where the platform is confined to limited power, weight, and storage capacity. The availability of onboard data compression would help alleviate the impact of these issues while preserving the information contained in the hyperspectral image. We present herein a systematic review of hardware-accelerated compression of hyperspectral images targeting remote sensing applications. We reviewed a total of 101 papers published from 2000 to 2021. We present a comparative performance analysis of the synthesized results with an emphasis on metrics like power requirement, throughput, and compression ratio. Furthermore, we rank the best algorithms based on efficiency and elaborate on the major factors impacting the performance of hardware-accelerated compression. We conclude by highlighting some of the research gaps in the literature and recommend potential areas of future research.