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The Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) dynamically monitors water depth in shallow waters around islands and reefs. Noise removal is a prerequisite for accurate reconstruction of seafloor topography based on ICESat-2 data products. To this end, we propose a density and distance-based method (DDBM) to extract seafloor signal photons from ICESat-2 data. The DDBM first separates the photons into three parts: above water, water surface, and water column. The water-column photons consist of seafloor signal photons and noise photons. The DDBM adopts a two-step denoising strategy to remove noise in water-column photons to obtain pure and complete signal photons. In the first step, an orientation-variable adaptive ellipse filter is developed, which can adaptively adjust the parameters according to the water depth to remove low-density noise photons. In the second step, a novel distance-based filter (DBF) is designed for stubborn high-density noise clusters. These noise clusters are far from the signal photons, and the DBF removes them by a distance threshold derived from the Otsu threshold method. We select three high-density ICESat-2 datasets to validate the DDBM. Compared with the reference data, the comprehensive evaluation indexes $F$ of the DDBM in all datasets are above 0.99, and the highest is 0.998, showing superior performance. [ABSTRACT FROM AUTHOR]

A novel packaging method that enables the reliable mounting and protection of bare die within a textile yarn has been investigated. The reliability of electronic textiles is highly challenging given the flexibility of the fabric and the rigors of typical applications. Achieving reliable operation requires novel packaging approaches. In order to maximize the reliability and to minimize stresses in the electronic package, the die should be located as close as possible to the central axis of the overall assembly. The die is bonded to a bottom Kapton substrate that contains patterned conductive interconnects and bond pads forming the functional circuit. The circuit is protected by a molded Kapton film that has recesses formed where the die is located. This approach has been compared with three other traditional packaging technologies during washing, twisting, and cyclical bending tests. The novel electronic packaging method shows the best performance in all tests surviving up to 45 wash cycles. [ABSTRACT FROM AUTHOR]

A method for packaging integrated circuit silicon die in thin flexible circuits has been investigated that enables circuits to be subsequently integrated within textile yarns. This paper presents an investigation into the required materials and component dimensions in order to maximize the reliability of the packaging method. Two die sizes of 3.5 \,\,\text mm \times 8 \,\,\text mm \times 0.53\,\, \text mm and 2 \,\,\text mm \times 2\,\,\text mm \times 0.1 \,\,\text mm have been simulated and evaluated experimentally under shear load and during bending. The shear and bending experimental results show good agreement with the simulation results and verify the simulated optimal thickness of the adhesive layer. Three underfill adhesives (EP30AO, EP37-3FLF, and Epo-Tek 301 2fl), three highly flexible adhesives (Loctite 4860, Loctite 480, and Loctite 4902), and three substrates (Kapton, Mylar, and PEEK) have been evaluated, and the optimal thickness of each is found. The Kapton substrate, together with the EP37-3FLF adhesive, was identified as the best materials combination with the optimum underfill and substrate thickness identified as 0.05 mm. [ABSTRACT FROM AUTHOR]