Deep Learning-Based Object Detection in Maritime Unmanned Aerial Vehicle Imagery: Review and Experimental Comparisons

With the advancement of maritime unmanned aerial vehicles (UAVs) and deep learning technologies, the application of UAV-based object detection has become increasingly significant in the fields of maritime industry and ocean engineering. Endowed with intelligent sensing capabilities, the maritime UAVs enable effective and efficient maritime surveillance. To further promote the development of maritime UAV-based object detection, this paper provides a comprehensive review of challenges, relative methods, and UAV aerial datasets. Specifically, in this work, we first briefly summarize four challenges for object detection on maritime UAVs, i.e., object feature diversity, device limitation, maritime environment variability, and dataset scarcity. We then focus on computational methods to improve maritime UAV-based object detection performance in terms of scale-aware, small object detection, view-aware, rotated object detection, lightweight methods, and others. Next, we review the UAV aerial image/video datasets and propose a maritime UAV aerial dataset named MS2ship for ship detection. Furthermore, we conduct a series of experiments to present the performance evaluation and robustness analysis of object detection methods on maritime datasets. Eventually, we give the discussion and outlook on future works for maritime UAV-based object detection. The MS2ship dataset is available at \href{https://github.com/zcj234/MS2ship}{https://github.com/zcj234/MS2ship}.Comment: 32 pages, 18 figure

An efficient route for electrooxidation of methanol to dimethoxymethane using ionic liquid as electrolyte

An ionic liquid 1-ethyl-3-methyl imidazolium tetrafloroborate (EmimBF4) was found to be highly active for one-pot synthesis of dimethoxymethane (DMM) by electrooxidation of methanol on platinum electrode, exhibiting 34.7% conversion, 96.9% selectivity to DMM, high current efficiency (99.2%) as well. The electrode reaction mechanism was proposed according to the experimental results and reported literature

Effect of pectin on properties of potato starch after dry heat treatment

Purpose: To evaluate the effect of pectin on the properties of potato starch after dry heat treatment. Methods: Rapid visco analyzer (RVA), differential scanning calorimetry (DSC), texture profile analyzer (TPA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and x-ray diffractometry (XRD) were used to determine the properties of modified potato starch and pectin blends after dry heat treatment. Results: Results from RVA showed that the peak viscosity of modified potato starch decreased gradually with increase in pectin concentration, dry heat time and dry heat temperature, while starch breakdown decreased and setback was increased to varying degrees. The lowest breakdown was 792 cP at dry heat temperature of 140 °C. Modified potato starch had broader ranges of gelatinization temperatures and lower gelatinization enthalpy than raw potato starch. Dry heat treatment improved the hardness, gumminess and chewiness of the gels of modified potato starch and pectin blends SEM micrographs showed some cluster shapes in microstructure after dry heat treatment of starch-pectin blends. Infrared spectra revealed that pectin addition and dry heat treatment did not cause changes in starch structure. However, x-ray diffractograms indicated that dry heat treatment weakened the third peak of potato starch. Conclusion: These results indicate that dry heat treatment effectively alters the properties of potato starch and pectin blends. This finding broadens the applications of modified potato starch in food and pharmaceutical industries

The Structural Characterization and Antigenicity of the S Protein of SARS-CoV

The corona-like spikes or peplomers on the surface of the virion under electronic microscope are the most striking features of coronaviruses. The S (spike) protein is the largest structural protein, with 1,255 amino acids, in the viral genome. Its structure can be divided into three regions: a long N-terminal region in the exterior, a characteristic transmembrane (TM) region, and a short C-terminus in the interior of a virion. We detected fifteen substitutions of nucleotides by comparisons with the seventeen published SARS-CoV genome sequences, eight (53.3%) of which are non-synonymous mutations leading to amino acid alternations with predicted physiochemical changes. The possible antigenic determinants of the S protein are predicted, and the result is confirmed by ELISA (enzyme-linked immunosorbent assay) with synthesized peptides. Another profound finding is that three disulfide bonds are defined at the C-terminus with the N-terminus of the E (envelope) protein, based on the typical sequence and positions, thus establishing the structural connection with these two important structural proteins, if confirmed. Phylogenetic analysis reveals several conserved regions that might be potent drug targets

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead