Understanding Data Augmentation from a Robustness Perspective

In the realm of visual recognition, data augmentation stands out as a pivotal technique to amplify model robustness. Yet, a considerable number of existing methodologies lean heavily on heuristic foundations, rendering their intrinsic mechanisms ambiguous. This manuscript takes both a theoretical and empirical approach to understanding the phenomenon. Theoretically, we frame the discourse around data augmentation within game theory's constructs. Venturing deeper, our empirical evaluations dissect the intricate mechanisms of emblematic data augmentation strategies, illuminating that these techniques primarily stimulate mid- and high-order game interactions. Beyond the foundational exploration, our experiments span multiple datasets and diverse augmentation techniques, underscoring the universal applicability of our findings. Recognizing the vast array of robustness metrics with intricate correlations, we unveil a streamlined proxy. This proxy not only simplifies robustness assessment but also offers invaluable insights, shedding light on the inherent dynamics of model game interactions and their relation to overarching system robustness. These insights provide a novel lens through which we can re-evaluate model safety and robustness in visual recognition tasks.Comment: Not published yet. arXiv admin note: text overlap with arXiv:2212.0405

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Reflective nonlinear optical limiter design based on coupled Tamm plasmon polaritons and optical Kerr effect

With the increasing applications of high-power lasers in fields such as laser fabrication, laser measurement, laser therapy and scientific research, there is an increasing demand for high-performance nonlinear optical limiters (NOLs) to protect human eyes and optical sensitive elements. Here we propose a brand-new approach to design a reflective NOL with an ultra-wide stop band based on coupled Tamm plasmon polaritons (TPPs) and optical Kerr effect. The NOL permits the transmission of weak signal light at the desired wavelength while effectively blocking potentially harmful or accidentally intense lasers at the same wavelength to avoid damage to sensitive optical elements or human eyes. The design can be optimized for the desired operating wavelength and threshold intensity by using different dielectric layers. In a proof-of-concept design, taking the 1064 nm laser as an example, we design a NOL capable of dynamically adjusting its transmission in response to laser intensity. The NOL has a high transmission of 85.21 % at weak light (intensity less than 0.20 MW/cm2), and the transmission can be rapidly reduced to 1.39 % when the incident light intensity increases to 60.37 MW/cm2. Furthermore, the broad stop band effectively safeguards the limiter from potential damage caused by intense light at different wavelengths. Our proposed limiter exhibits an exceptionally wide stop band range spanning from 0.5 ∼ 20 µm, nearly 30 times broader than conventional reflective NOLs. The proposed NOL design scheme provides a new promising method to design an excellent reflective NOL at the desired wavelength

Extending the Effective Ranging Depth of Spectral Domain Optical Coherence Tomography by Spatial Frequency Domain Multiplexing

We present a spatial frequency domain multiplexing method for extending the imaging depth range of a spectral domain optical coherence tomography (SDOCT) system without any expensive device. This method uses two galvo scanners with different pivot-offset distances in two independent reference arms for spatial frequency modulation and multiplexing. The spatial frequency contents corresponding to different depth regions of the sample can be shifted to different frequency bands. The spatial frequency domain multiplexing SDOCT system provides an approximately 1.9-fold increase in the effective ranging depth compared with that of a conventional full-range SDOCT system. The reconstructed images of phantom and biological tissue demonstrate the expected increase in ranging depth. The parameters choice criterion for this method is discussed