Towards Trustworthy Dataset Distillation

Efficiency and trustworthiness are two eternal pursuits when applying deep learning in real-world applications. With regard to efficiency, dataset distillation (DD) endeavors to reduce training costs by distilling the large dataset into a tiny synthetic dataset. However, existing methods merely concentrate on in-distribution (InD) classification in a closed-world setting, disregarding out-of-distribution (OOD) samples. On the other hand, OOD detection aims to enhance models' trustworthiness, which is always inefficiently achieved in full-data settings. For the first time, we simultaneously consider both issues and propose a novel paradigm called Trustworthy Dataset Distillation (TrustDD). By distilling both InD samples and outliers, the condensed datasets are capable to train models competent in both InD classification and OOD detection. To alleviate the requirement of real outlier data and make OOD detection more practical, we further propose to corrupt InD samples to generate pseudo-outliers and introduce Pseudo-Outlier Exposure (POE). Comprehensive experiments on various settings demonstrate the effectiveness of TrustDD, and the proposed POE surpasses state-of-the-art method Outlier Exposure (OE). Compared with the preceding DD, TrustDD is more trustworthy and applicable to real open-world scenarios. Our code will be publicly available.Comment: 20 pages, 20 figure

Provably Secure Public Key Cryptosystem Based on Chebyshev Polynomials

Abstract-Chebyshev polynomials based public key cryptosystem (CPPKC), proposed by L. Kocarev in 2003, has emerged as a new research field in cryptography and attracted a lot of attentions in recent years. Although provable security in traditional public key cryptosystem has already been developed about twenty years, no relevant security proof research has been found about CPPKC. Aiming at the disability of CPPKC to resist against the adaptive chosen ciphertext attack, we construct a provably secure CPPKC, namely PS-CPPKC, which is designed utilizing the benefits of hash function and its security proof is completed under the Cheybshev Diffie-Hellman problem (CDHP) assumption by probabilistic analyses and computation in random oracle model. This is our primary exploration and it shows that provable security theory can combine well with CPPKC. Index Terms-Chebyshev polynomials, public key cryptosystem, chosen ciphertext attack, provable securit

Correlation of an epigenetic mitotic clock with cancer risk.

BACKGROUND: Variation in cancer risk among somatic tissues has been attributed to variations in the underlying rate of stem cell division. For a given tissue type, variable cancer risk between individuals is thought to be influenced by extrinsic factors which modulate this rate of stem cell division. To date, no molecular mitotic clock has been developed to approximate the number of stem cell divisions in a tissue of an individual and which is correlated with cancer risk. RESULTS: Here, we integrate mathematical modeling with prior biological knowledge to construct a DNA methylation-based age-correlative model which approximates a mitotic clock in both normal and cancer tissue. By focusing on promoter CpG sites that localize to Polycomb group target genes that are unmethylated in 11 different fetal tissue types, we show that increases in DNA methylation at these sites defines a tick rate which correlates with the estimated rate of stem cell division in normal tissues. Using matched DNA methylation and RNA-seq data, we further show that it correlates with an expression-based mitotic index in cancer tissue. We demonstrate that this mitotic-like clock is universally accelerated in cancer, including pre-cancerous lesions, and that it is also accelerated in normal epithelial cells exposed to a major carcinogen. CONCLUSIONS: Unlike other epigenetic and mutational clocks or the telomere clock, the epigenetic clock proposed here provides a concrete example of a mitotic-like clock which is universally accelerated in cancer and precancerous lesions

New Aggregation-Induced Delayed Fluorescence Luminogens With Through-Space Charge Transfer for Efficient Non-doped OLEDs

In this work, two tailor-made luminogens comprising of electron donors (acridine and phenoxazine) and acceptor (triazine) bridged by the through-space conjugated hexaphenylbenzene (HPB) are synthesized and characterized. Their thermal stability, electrochemical behaviors, crystal, and electronic structures, and photophysical properties are systematically investigated. The crystal and electronic structures reveal that the peripheral phenyls in HPB are closely aligned in a propeller-like fashion, rendering efficient through-space charge transfer between donor and electron moieties. These molecules display weak fluorescence with negligible delayed component in solutions but strong fluorescence with greatly increased delayed component upon aggregate formation, namely aggregation-induced delayed fluorescence (AIDF). Their neat films exhibit high photoluminescence quantum yields (PLQY), and prominent delayed fluorescence. The non-doped organic light-emitting diodes (OLEDs) based on these new luminogens exhibit excellent performance with maximum external quantum efficiency of 12.7% and very small efficiency roll-off of 2.7% at 1,000 cd m−2. Designing AIDF molecules with through-space charge transfer could be a promising strategy to explore robust luminescent materials for efficient non-doped OLEDs

Essential Technology and Application of Jitter Detection and Compensation for High Resolution Satellites

Satellite jitter is a common and complex phenomenon for the on-orbit high resolution satellites, which may affect the mapping accuracy and quality of imagery. A framework of jitter detection and compensation integrating data processing of multiple sensors is proposed in this paper. Jitter detection is performed based on multispectral imagery, three-line-array imagery, dense ground control and attitude measurement data, and jitter compensation is conducted both on image and on attitude with the sensor model. The platform jitter of ZY-3 satellite is processed and analyzed using the proposed technology, and the results demonstrate the feasibility and reliability of jitter detection and compensation. The variation law analysis of jitter indicates that the frequencies of jitter of ZY-3 satellite hold in the range between 0.6 and 0.7 Hz, while the amplitudes of jitter of ZY-3 satellite drop from 1 pixel in the early stage to below 0.4 pixels and tend to remain stable in the following stage

Simulation of photoexcitation dynamics in conjugated polymer using Ehrenfest method with configuration interaction singles

Ehrenfest method is commonly used for simulating photoexcitation dynamics in conjugated polymers. However, due to the expensive computational cost, the calculation of electronic excited states for long conjugated polymer chains in Ehrenfest simulations is still at the level of Hartree–Fock approximation. Here, we develop an approach to perform Ehrenfest simulations in terms of configuration interaction singles (CIS) that is beyond the Hartree–Fock approximation. With this approach, we simulate the relaxations of various photoinduced excited states in a single polymer chain. The simulations show that the photoinduced excited states relax to a mixed state very fast, in which the lowest excited state is dominated.In the excited-state relaxation processes, the electron and hole are not separated. We have also studied the exciton dissociation by external electric field, and find that the critical electric field to dissociate the exciton is much lower than that calculated by previous Ehrenfest simulations in terms of low-level excited-state calculations

Exploring interchain polaron pair formation in neat conjugated polymers

We present theoretical studies to explore interchain polaron pair (PP) formation in conjugated polymers. Based on the Pariser-Parr-Pople (PPP) Hamiltonian combined with the configuration interaction singles (CIS), we perform excited-state geometry optimization on a poly-p-phenylenevinylene (PPV) dimer, and identify interchain PPs in this system by analyzing the real-space distributions of electron and hole in different excited states. We find that interchain PP states can not form in highly symmetric cofacial PPV-dimer, but can form in this PPV-dimer when applying an external electric field, rotating one of two chains, or doping an impurity. Considering that highly symmetric systems are hardly present in real polymer films, PPs should commonly exist as high-lying excited states of real polymer systems

Determination of the Height of the Water-Conducting Fractured Zone in Difficult Geological Structures: A Case Study in Zhao Gu No. 1 Coal Seam

The method for determining the upper limit for safe mining with regard to water and sand collapse prevention under thick alluvium and thin bedrock layers is a critical parameter for ensuring the sustainable development of a mine. The height of the water-conducting fractured zone (HWCFZ) is an important index parameter in the prediction and prevention of water and sand collapse. This research was conducted based on the concrete geological condition of the Zhao Gu No. 1 coal mine. First, a field measurement method was used to observe the HWCFZ of a mined panel. The discrete element method was applied to establish a corresponding model, which was calibrated using the measurement data. Then, calculation models for different bedrock thicknesses were developed to analyze the evolution law of the water-conducting fractured zone at different bedrock thicknesses and mining heights. The safe mining upper limits for different bedrock thicknesses were obtained. The relationships between the developing HWCFZ and bedrock thickness/mining height were determined. Using the research results as the main indices, an industrial experiment was performed on the 11,191 panel. The partition limit mining height was implemented in the panel, and safe production was realized. On the basis of the research results, 40,199,336.3 t of coal resources were successfully released, increasing the resource recovery rate by 31.72% and extending the mine service life by 12.5 years. This study not only provided technical support for the sustainable development of the Zhao Gu No. 1 coal seam, but could also be used for safe and highly efficient mining in other coal mines under similar geological conditions